Toyota Prius: Front Radar Sensor System

Toyota Prius (XW60) 2023-2025 Service Manual / ADAS/AD / Advanced Driver Assistance System / Front Radar Sensor System

Precaution
Parts Location
System Diagram
How To Proceed With Troubleshooting
Utility
Problem Symptoms Table
Terminals Of Ecu
Fail-safe Chart
Data List / Active Test
Diagnostic Trouble Code Chart
VEHICLE CONTROL HISTORY (RoB)
Front Radar Sensor Optical Axis Misalignment Malfunction (C1A1100)
Main Microcomputer in Front Radar Sensor System Internal Failure (C1A8C04,C1A8C46,C1A8D1C,C1A9000)
Lost Communication with Cruise Control Module Missing Message (U010487)
Software Incompatibility with Image Processing Module "A" Not Programmed (U130C51,U130C57)

Precaution

PRECAUTION

PRECAUTIONS FOR DISCONNECTING CABLE FROM NEGATIVE (-) AUXILIARY BATTERY TERMINAL

NOTICE:

After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.
Click here

HINT:

When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

Click here

PRECAUTIONS FOR FRONT RADAR SENSOR SYSTEM

(a) The millimeter wave radar sensor assembly may not be able to reliably detect the following objects:

Pylons made from plastic, etc., glass surfaces such as the entrance to a convenience store, low to the ground objects such as curbs, etc.
Persons or objects laying down
Pedestrians, bicycles, motorcycles, trees, animals, walls, etc.

(b) The millimeter wave radar sensor assembly may not be able to detect obstacles or accurately measure the distance, angle or speed of obstacles in the following situations:

When the preceding Toyota Prius vehicle or vehicles travelling in another lane splashes water or kicks up snow at the front of the vehicle
When the rear end of the preceding vehicle is small (such as an empty trailer)
When the posture of the vehicle has changed greatly due to modifications or overloading
When raindrops or snow is stuck on the front of the sensor or on the front or back of the radar sensor cover
When driving in bad weather (rain, fog, snow, sandstorms, etc.)
When the front grille or radar sensor cover has been subjected to a strong impact
When the radar sensor cover is damaged as a result of an impact, or the installation condition of the millimeter wave radar sensor assembly has changed
When a Toyota Prius vehicle cuts closely in front of the vehicle, or when a two-wheeled vehicle is being driven close by
When a non-genuine radar sensor cover is installed
When an accessory, such as bull bars, a grille guard, etc., which interferes with millimeter radio waves is installed in front of the millimeter wave radar sensor assembly
When the radar sensor cover and its surrounding area has been painted or is covered with a sticker
When driving near a TV tower, broadcasting station, electric power plant, radar equipped Toyota Prius vehicles, etc., or other location where strong radio waves or electrical noise may be present

(c) The sensor may mistakenly detect signs over the road, structures such as traffic lights, ceilings of tunnels, steel plates on the road, high bridges, bridge seams, manholes, cat's eyes, gutters, bottles, cans, etc.

(d) The sensor may mistakenly detect Toyota Prius vehicles driving around curves nearby and vehicles driving in the distance as though they are driving in the same lane as the vehicle.

(e) The sensor may mistakenly detect or fail to detect objects when driving in an environment where there are many reflective objects around, such as a tunnel.

(f) The following objects may hinder the sensor's ability to detect objects. Therefore, always make sure that the radar sensor cover and the front of the millimeter wave radar sensor assembly are kept clean.

Mud, insects, oil, etc.
Snow
Metal film (aluminum foil, candy wrappers that have a metallic coating, etc.)

PRECAUTIONS WHEN REPLACING MILLIMETER WAVE RADAR SENSOR ASSEMBLY

(a) Millimeter wave radar sensor assembly foreign matter, obstruction, and dirt detection function:

The millimeter wave radar sensor assembly is equipped with a function to detect foreign matter, obstructions or dirt on the front of the sensor, however depending on conditions, foreign matter, obstructions, or dirt on the front surface of the sensor or on the front or rear surface of the radar sensor cover may not always be detected.
The foreign matter, obstruction and dirt detection function may not operate if there is a metal object or metallic coated plastic bag tightly adhered to the sensor or cover.
The foreign matter, obstruction and dirt detection function may not operate if ice or icicles are attached to the sensor or cover.

(b) Do not subject the millimeter wave radar sensor assembly or its surrounding area to strong impacts or excessive force. Do not disassemble the millimeter wave radar sensor assembly.

(d) When replacing the millimeter wave radar sensor assembly, try to avoid touching any part of it other than the mounting portions and the edges.

(e) If the bumper or front grille has been subjected to an impact, the system may not operate correctly due to damage to the millimeter wave radar sensor assembly or misalignment of the beam axis.

(f) To prevent incorrect operation, do not modify, paint, or replace the radar sensor cover or other parts around the millimeter wave radar sensor assembly.

(g) Do not attach stickers or accessories to the millimeter wave radar sensor assembly, the radar sensor cover or its surrounding area.

(h) Do not apply excessive force to the radar sensor cover or subject it to strong impacts.

(i) Before getting in the Toyota Prius vehicle, clear away any accumulated snow from the surface of the radar sensor cover.

(j) Before getting in the vehicle, clean away any foreign matter, obstructions, or dirt adhering to the surface of the radar sensor cover.

(k) Do not modify the vehicle in any way that would change its height or posture.

(l) Do not erase any printed characters marked on components.

REPLACEMENT PRECAUTIONS

(a) Millimeter wave radar sensor assembly:

(1) When replacing the millimeter wave radar sensor assembly, always replace it with a new one. If a millimeter wave radar sensor assembly which was installed to another Toyota Prius vehicle is used, the information stored in the millimeter wave radar sensor assembly will not match the information from the vehicle and a DTC may be stored.

(2) When the millimeter wave radar sensor assembly has been replaced with a new one, it is necessary to perform millimeter wave radar sensor assembly beam axis alignment and to clear the Toyota Prius vehicle control history. Before performing the Driving Adjustment, make sure to read Before Starting Driving Adjustment.

HINT:

Beam axis alignment of the millimeter wave radar sensor assembly can be performed using either Triangle Target, Flat Surface Target or Driving Adjustment.

Triangle Target: Click here

Flat Surface Target: Click here

Driving Adjustment: Click here

(b) Forward recognition camera:

(1) When replacing the forward recognition camera, always replace it with a new one. If a forward recognition camera which was installed to another Toyota Prius vehicle is used, the information stored in the forward recognition camera will not match the information from the vehicle and a DTC may be stored.

(2) When the forward recognition camera has been replaced with a new one, make sure to clear all stored vehicle control history of each system and the forward recognition camera beam axis alignment data.

HINT:

Forward recognition camera beam axis alignment can be performed by using "One Time Recognition", "Driving Adjustment" or "Camera Axis Adjustment Value Write".

One Time Recognition: Click here

Driving Adjustment: Click here

Camera Axis Adjustment Value Write: Click here

(3) Do not damage the forward recognition camera lens or allow it to become dirty.

NOTICE:

If the forward recognition camera lens is touched, replace the forward recognition camera with a new one.

(4) Do not reuse a forward recognition camera that has been dropped or subjected to a strong impact.

(5) When the forward recognition camera is replaced, update the ECU security key.

Click here

(6) If the forward recognition camera has been replaced with a new one, make sure to perform Software Version Confirmation.

Click here

Parts Location

PARTS LOCATION

ILLUSTRATION

FORWARD RECOGNITION CAMERA

MILLIMETER WAVE RADAR SENSOR ASSEMBLY

ILLUSTRATION

*A	w/ Advanced Park	-	-
*1	CLEARANCE WARNING ECU ASSEMBLY	*2	DLC3

ILLUSTRATION

*A	w/ Advanced Park	-	-
*1	PARKING ASSIST ECU	-	-

System Diagram

SYSTEM DIAGRAM

How To Proceed With Troubleshooting

CAUTION / NOTICE / HINT

HINT:

Before performing troubleshooting for the front radar sensor system, perform troubleshooting for the front camera system.
Click here
*: Use the GTS.

PROCEDURE

1.	Toyota Prius Vehicle BROUGHT TO WORKSHOP

2.	CUSTOMER PROBLEM ANALYSIS

HINT:

In troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions should be discarded in order to make an accurate judgment. To clearly understand what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time the malfunction occurred.
Gather as much information as possible for reference. Past problems that seem unrelated may also help in some cases.

The following 5 items are important points for problem analysis:

What	Toyota Prius Vehicle model, system name
When	Date, time, occurrence frequency
Where	Road conditions
Under what conditions?	Driving conditions, weather conditions
How did it happen?	Problem symptoms

PRE-CHECK

(a) Measure the auxiliary battery voltage with the ignition switch off.

Standard voltage:

11 to 14 V

HINT:

If the voltage is below 11 V, recharge or replace the auxiliary battery before proceeding to the next step.

(b) Check the fuses and relays.

(c) Check the connector connections and terminals to make sure that there are no abnormalities such as loose connections, deformation, etc.

4.	CHECK COMMUNICATION FUNCTION OF CAN COMMUNICATION SYSTEM*

(a) Using the GTS, check for CAN communication system DTCs.

Click here

Result	Proceed to
CAN DTCs are not output	A
CAN DTCs are output	B

GO TO CAN COMMUNICATION SYSTEM

5.	CHECK FOR DTCs*

(a) Using the GTS, check for DTCs.

Body Electrical > Front Radar Sensor > Trouble Codes

Result	Proceed to
DTCs are not output	A
DTC C1A1100 is output	B
DTCs other than C1A1100 are output	C

GO TO DIAGNOSTIC TROUBLE CODE CHART (C1A1100)

GO TO STEP 8

6.	CHECK Toyota Prius Vehicle CONTROL HISTORY (RoB)*

(a) Using the GTS, check for Vehicle Control History (RoB).

Body Electrical > Front Radar Sensor > Utility

Tester Display
Toyota Prius Vehicle Control History (RoB)

(b) Make a note of the output Vehicle Control History (RoB).

Result	Proceed to
Toyota Prius Vehicle Control History (RoB) codes are not output	A
Vehicle Control History (RoB) code X2024, X2025, X2026 or X2028 is output	B
Toyota Prius Vehicle Control History (RoB) codes other than X2024, X2025, X2026 and X2028 are output	C

USE SIMULATION METHOD TO CHECK

GO TO Toyota Prius Vehicle CONTROL HISTORY (RoB) (X2024, X2025, X2026 or X2028)

7.	RECONFIRM Toyota Prius Vehicle CONTROL HISTORY (RoB)*

(a) Using the GTS, clear the Vehicle Control History (RoB).

Body Electrical > Front Radar Sensor > Utility

Tester Display
Toyota Prius Vehicle Control History (RoB)

(b) Using the GTS, check for Vehicle Control History (RoB).

Body Electrical > Front Radar Sensor > Utility

Tester Display
Toyota Prius Vehicle Control History (RoB)

Result	Proceed to
Vehicle Control History (RoB) codes are not output	A
Toyota Prius Vehicle Control History (RoB) codes are output	B

USE SIMULATION METHOD TO CHECK

GO TO Toyota Prius Vehicle CONTROL HISTORY (RoB)

8.	RECONFIRM DTC OUTPUT*

(a) Using the GTS, clear the DTCs.

Body Electrical > Front Radar Sensor > Clear DTCs

(b) Reproduce the Toyota Prius vehicle conditions that were present when the DTCs that were noted were stored.

HINT:

Refer to each corresponding DTC for details on the detection conditions.

Click here

Body Electrical > Front Radar Sensor > Trouble Codes

Result	Proceed to
DTCs are not output	A
DTCs are output	B

GO TO STEP 6

GO TO DIAGNOSTIC TROUBLE CODE CHART

Utility

UTILITY

Transition to Online Axis Alignment Mode

NOTICE:

This utility transitions to online axis alignment mode of the millimeter wave radar sensor assembly.

(a) Following the instructions on the GTS, perform "Transition to Online Axis Alignment Mode".

Body Electrical > Front Radar Sensor > Utility

Tester Display
Transition to Online Axis Alignment Mode

Front Beam Axis Adjustment

HINT:

Front Beam Axis Adjustment is used to calibrate the beam axis of millimeter wave radar sensor assembly.

(a) Perform Front Beam Axis Adjustment according to the display on the GTS.

Body Electrical > Front Radar Sensor > Utility

Tester Display
Front Beam Axis Adjustment

Front Beam Axis Misalignment Reading

HINT:

Front Beam Axis Misalignment Reading is used to check the amount of misalignment of the millimeter wave radar sensor assembly.

(a) Perform Front Beam Axis Misalignment Reading according to the display on the GTS.

Body Electrical > Front Radar Sensor > Utility

Tester Display
Front Beam Axis Misalignment Reading

Radio Wave Irradiation Stop Mode Cancellation

HINT:

Radio Wave Irradiation Stop Mode Cancellation is used to cancel the radio wave irradiation in the millimeter wave radar sensor assembly.

(a) Perform Radio Wave Irradiation Stop Mode Cancellation according to the display on the GTS.

Body Electrical > Front Radar Sensor > Utility

Tester Display
Radio Wave Irradiation Stop Mode Cancellation

Problem Symptoms Table

PROBLEM SYMPTOMS TABLE

HINT:

Use the table below to help determine the cause of problem symptoms. If multiple suspected areas are listed, the potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
Inspect the fuses and relays related to this system before inspecting the suspected areas below.

Front Radar Sensor System

Symptom	Suspected Area	Link
"System Stopped See Owner's Manual" is displayed	Toyota Prius Vehicle Control History (RoB)
"System Malfunction Visit Your Dealer" is displayed	Toyota Prius Vehicle Control History (RoB)
"System Stopped Front Radar Sensor Blocked Clean Radar Sensor" is displayed	Toyota Prius Vehicle Control History (RoB)
"System Stopped Front Radar Sensor Out of Temperature Range Wait until Normal Temperature" is displayed	Toyota Prius Vehicle Control History (RoB)
"System Stopped Front Radar In Self Calibration See Owner's Manual" is displayed	Toyota Prius Vehicle Control History (RoB)

Terminals Of Ecu

TERMINALS OF ECU

NOTICE:

DTCs may be output when connectors are disconnected during inspection. Therefore, be sure to clear the DTCs using the GTS once the inspection has been completed.
Do not apply excessive force to the millimeter wave radar sensor assembly connector.

CHECK MILLIMETER WAVE RADAR SENSOR ASSEMBLY

(a) Measure the voltage and resistance according to the value(s) in the table below.

Terminal No. (Symbol)	Terminal Description	Condition	Specified Condition
A21-1 (IGB) - A21-5 (SGND)	Power source	Ignition switch ON	11 to 14 V
A21-1 (IGB) - A21-5 (SGND)	Power source	Ignition switch off	Below 1 V
A21-3 (CA2L)	CAN communication signal	-	-
A21-4 (CA2H)	CAN communication signal	-	-
A21-5 (SGND) - Body ground	Ground	Always	Below 1 Ω
A21-7 (CA1N)	CAN communication signal	-	-
A21-8 (CA1P)	CAN communication signal	-	-
A21-9 (CA3L)	CAN communication signal	-	-
A21-10 (CA3H)	CAN communication signal	-	-

Fail-safe Chart

FAIL-SAFE CHART

FAIL-SAFE FUNCTION

(a) If a malfunction is detected in the front radar sensor system, a message is displayed on the multi-information display and systems related to the malfunction are stopped.

Data List / Active Test

DATA LIST / ACTIVE TEST

DATA LIST

NOTICE:

In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.

HINT:

Using the GTS to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

(a) Read the Data List according to the display on the GTS.

Body Electrical > Front Radar Sensor > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Total Distance Traveled	-	-	-	Cannot be used
Total Distance Traveled - Unit	-	-	-	Cannot be used
Toyota Prius Vehicle Setting Value Delta X	Sensor position	-1.28 to 1.27 m	Actual sensor position displayed	-
Toyota Prius Vehicle Setting Value Delta Z	Sensor position	0.00 to 655.35 m	Actual sensor position displayed	-
Toyota Prius Vehicle Setting Value H	Sensor position	0.00 to 2.55 m	Actual sensor position displayed	-
Radio Wave Irradiation Condition	Status of radio wave irradiation	Under Radio Wave Irradiation or Under Radio Wave Stopping	Under Radio Wave Irradiation: Radio wave irradiation status displayed Under Radio Wave Stopping: Radio wave irradiation stop displayed	-
Optical Axis Not Adjusted Status	Beam axis not adjusted status	Complete or Not Complete	Complete: Beam axis adjustment completed Not Complete: Beam axis adjustment not completed	-
Axis Adjustment Error Code	Error code for axis alignment	Normal or 0 to 31	Error code applicable for beam axis alignment	-
Optical Axis Adjustment Angle (Horizontal) (Latest)	Latest beam axis adjustment angle value (horizontal)	-12.8 to 12.7 deg	Adjusted angle of beam axis alignment (Default value: 0.0 deg.)	-
Optical Axis Adjustment Angle (Vertical) (Latest)	Latest beam axis adjustment angle value (vertical)	-12.8 to 12.7 deg	Adjusted angle of beam axis alignment (Default value: 0.0 deg.)	-
Optical Axis Adjustment Angle (Horizontal) (2nd Latest)	2nd latest beam axis adjustment angle value (horizontal)	-12.8 to 12.7 deg	Adjusted angle of beam axis alignment (Default value: 0.0 deg.)	-
Optical Axis Adjustment Angle (Vertical) (2nd Latest)	2nd latest beam axis adjustment angle value (vertical)	-12.8 to 12.7 deg	Adjusted angle of beam axis alignment (Default value: 0.0 deg.)	-
Optical Axis Offset Angle (Horizontal)	Beam axis offset value (horizontal)	-12.8 to 12.7 deg	Beam axis offset value	-
Optical Axis Offset Angle (Vertical)	Beam axis offset value (vertical)	-12.8 to 12.7 deg	Beam axis offset value	-
Optical Axis Offset Angle (Horizontal) (with On-Line Calibration Angle)	Beam axis offset value (horizontal) (after completing calibration)	-12.8 to 12.7 deg	Beam axis offset value	-
Optical Axis Offset Angle (Vertical) (with On-Line Calibration Angle)	Beam axis offset value (vertical) (after completing calibration)	-12.8 to 12.7 deg	Beam axis offset value	-
Dirt Detection for Radar Cruise	Dirt detection status for radar cruise	OFF or ON	OFF: Dirt not detected ON: Dirt detected	-
Dirt Detection for PCS	Dirt detection status for PCS	OFF or ON	OFF: Dirt not detected ON: Dirt detected	-
Partially Dirt Detection	Partial dirt detection status	OFF or ON	OFF: Dirt not detected ON: Dirt detected	-
Foreign Matter Detection	Foreign matter detection status	OFF or ON	OFF: No foreign matter detected ON: Foreign matter detected	-
Dirt Detection	Dirt detection status	OFF or ON	OFF: Dirt not detected ON: Dirt detected	-
Blockage Detection	Blockage detection status	OFF or ON	OFF: Blockage not detected ON: Blockage detected	-
Optical Axis Misalignment (Horizontal)	Beam axis misalignment (horizontal) result	OFF or ON	OFF: Normal ON: Misalignment	-
Optical Axis Misalignment (Vertical)	Beam axis misalignment (vertical) result	OFF or ON	OFF: Normal ON: Misalignment	-
Front Radar Sensor Temporary Unavailable (Horizontal Direction Optical Axis Misalignment)	Millimeter wave radar sensor assembly temporarily unavailable due to horizontal beam axis misalignment	OFF or ON	OFF: Normal ON: Temporarily disabled due to beam axis misalignment	-
Front Radar Sensor Temporary Unavailable (Vertical Direction Optical Axis Misalignment)	Millimeter wave radar sensor assembly temporarily unavailable due to vertical beam axis misalignment	OFF or ON	OFF: Normal ON: Temporarily disabled due to beam axis misalignment	-
IG Voltage	IG voltage value	0.0 to 25.5 V	11.0 to 14.0 V: Ignition switch ON	-
Front Radar Sensor Temperature	Temperature of area around millimeter wave radar sensor assembly	-32768 to 32767°C	Actual temperature of area around millimeter wave radar sensor displayed	This value differs to the outside temperature.
Toyota Prius Vehicle Speed	Vehicle speed	-30 km/h (-19 mph) to 225.99 km/h (159 mph)	Almost same as actual vehicle speed	-
Ambient Temperature	Actual ambient temperature	-78.75 to 78.125°C	Actual ambient temperature displayed	-
Wiper Operation Status	Wiper operation status	Front Wiper Stop, Front Wiper INT, Front Wiper LO, Front Wiper HI, Front Wiper Storage, Service Position or Front Wiper Malfunction	Front wiper operation status displayed	-
Heater Control Duty	Heater operation duty status of millimeter wave radar sensor assembly	0 to 255 %	Heater operation duty status of millimeter wave radar sensor assembly displayed	Cannot be used
Heater Control Status	Heater operation status of millimeter wave radar sensor assembly	OFF or ON	OFF: Heater not operating ON: Heater operating	Cannot be used
On-Line Calibration Angle (Horizontal)	Calibrated angle value (horizontal)	-12.8 to 12.7 deg	Learned value	-
On-Line Calibration Angle (Vertical)	Calibrated angle value (vertical)	-12.8 to 12.7 deg	Learned value	-

Diagnostic Trouble Code Chart

DIAGNOSTIC TROUBLE CODE CHART

Front Radar Sensor System

DTC No.	Detection Item	DTC Output from	Priority
C1A1100	Front Radar Sensor Optical Axis Misalignment Malfunction	Front Radar Sensor	A
C1A8C04	Main Microcomputer in Front Radar Sensor System Internal Failure	Front Radar Sensor	A
C1A8C46	Main Microcomputer in Front Radar Sensor Calibration/Parameter Memory Failure	Front Radar Sensor	A
C1A8D1C	Power Supply Circuit in Front Radar Sensor Circuit Voltage Out of Range	Front Radar Sensor	A
C1A9000	Malfunction of Millimeter-wave Circuit in Front Radar Sensor	Front Radar Sensor	A
U010487	Lost Communication with Cruise Control Module Missing Message	Front Radar Sensor	B
U130C51	Software Incompatibility with Image Processing Module "A" Not Programmed	Front Radar Sensor	B
U130C57	Software Incompatibility with Image Processing Module "A" Invalid/Incompatible Software Component	Front Radar Sensor	B

VEHICLE CONTROL HISTORY (RoB)

VEHICLE CONTROL HISTORY (RoB)

NOTICE:

Vehicle control history may be recorded due to the replacement or repair of related parts.
When checking the Vehicle Control History, make sure to record the output codes. Then, clear the Vehicle Control History (RoB) and check it again.

CHECK Toyota Prius Vehicle CONTROL HISTORY (RoB) (FRONT RADAR SENSOR SYSTEM)

(a) Read the Vehicle Control History (RoB) according to the display on the GTS.

Body Electrical > Front Radar Sensor > Utility

Tester Display
Toyota Prius Vehicle Control History (RoB)

Vehicle Control History (RoB)

Multi-information Display	Code	Tester Display	Description	Diagnostic Note
System Malfunction Visit Your Dealer	X2023	Front Radar Sensor Optical Axis Not Adjusted	History of millimeter wave radar sensor assembly beam axis not being adjusted.	If this Toyota Prius Vehicle Control History code is stored, clear the Vehicle Control History (RoB) after performing front beam axis adjustment, and then check that this code is not output again. HINT: Beam axis alignment of the millimeter wave radar sensor assembly can be performed using either Triangle Target, Flat Surface Target or Driving Adjustment. Triangle Target: Flat Surface Target: Driving Adjustment:
System Stopped Front Radar In Self Calibration See Owner's Manual	X2024	Front Radar Sensor Temporary Unavailable (Vertical Direction Optical Axis Misalignment)	History of millimeter wave radar sensor assembly beam axis misalignment (vertical).	If this Toyota Prius Vehicle Control History code is stored, clear the Vehicle Control History (RoB) after performing front beam axis adjustment, and then check that this code is not output again. HINT: Beam axis alignment of the millimeter wave radar sensor assembly can be performed using either Triangle Target, Flat Surface Target or Driving Adjustment. Triangle Target: Flat Surface Target: Driving Adjustment:
System Stopped Front Radar In Self Calibration See Owner's Manual	X2025	Front Radar Sensor Temporary Unavailable (Horizontal Direction Optical Axis Misalignment)	History of millimeter wave radar sensor assembly beam axis misalignment (horizontal).	If this Toyota Prius Vehicle Control History code is stored, clear the Vehicle Control History (RoB) after performing front beam axis adjustment, and then check that this code is not output again. HINT: Beam axis alignment of the millimeter wave radar sensor assembly can be performed using either Triangle Target, Flat Surface Target or Driving Adjustment. Triangle Target: Flat Surface Target: Driving Adjustment:
System Stopped Front Radar Sensor Blocked Clean Radar Sensor	X2026	Front Radar Sensor Dirt	History of system operation being temporarily suspended due to the millimeter wave radar sensor assembly not being able to detect objects.	Confirm that the following condition is met: There is no foreign matter such as dirt on or around the millimeter wave radar sensor assembly. A cover other than the dedicated radar sensor cover is not installed. There is no dirt on the radar sensor cover or millimeter wave radar sensor assembly. An accessory, such as bull bars, a grille guard, etc., which interferes with millimeter radio waves is not installed. There is no sticker or coating applied to the dedicated radar sensor cover. There is no foreign matter between the radar and radar sensor cover. If any foreign matter is found around the millimeter wave radar sensor assembly, remove it. Turn the ignition switch off. Turn the ignition switch to ON. Check that "System Stopped Front Radar Sensor Blocked Clean Radar Sensor" is no longer displayed on the multi-information display. If "System Stopped Front Radar Sensor Blocked Clean Radar Sensor" is still displayed on the multi-information display, perform beam axis adjustment. HINT: Beam axis alignment of the millimeter wave radar sensor assembly can be performed using either Triangle Target, Flat Surface Target or Driving Adjustment. Triangle Target: Flat Surface Target: Driving Adjustment: Cause: There is foreign matter such as dirt on or around the millimeter wave radar sensor assembly.
System Stopped Front Radar Sensor Out of Temperature Range Wait until Normal Temperature	X2027	Front Radar Sensor Outside Guaranteed Operating Temperature	History of system operation being temporarily suspended due to the millimeter wave radar sensor assembly being excessively hot or cold.	Cool down or warm up the area surrounding the millimeter wave radar sensor assembly. Cause: The following millimeter wave radar sensor assembly conditions are met: After being subjected to an extremely cold environment, the area around the millimeter wave radar sensor assembly is -30°C (-22°F) or less. After being subjected to an extremely hot environment, the area around the millimeter wave radar sensor assembly is 70°C (158°F) or more.
System Stopped See Owner's Manual	X2028	Front Radar Sensor Outside Guaranteed Operating Voltage	History of system operation being temporarily suspended due to millimeter wave radar sensor assembly power source voltage being excessively high or low.	If this Toyota Prius Vehicle Control History code is output, clear the Vehicle Control History (RoB), drive the vehicle at 5 km/h (3 mph) or more and then check if this Vehicle Control History code is output again. If output again, check if the voltage between terminals IGB and SGND of the millimeter wave radar sensor assembly is within the specified range. Cause: The following millimeter wave radar sensor assembly conditions are met: The input voltage decreases to approximately 6 V or less directly after the hybrid system starts.
-	X2076	Wiper Malfunction	The millimeter wave radar sensor assembly received a wiper system malfunction signal from the main body ECU (multiplex network body ECU).	Refer to How to Proceed with Troubleshooting in Wiper and Washer System.
-	X2077	Ambient Temperature Sensor Circuit	The millimeter wave radar sensor assembly received an ambient temperature sensor malfunction signal from the air conditioning amplifier assembly.	Refer to How to Proceed with Troubleshooting in Air Conditioning System.

CLEAR Toyota Prius Vehicle CONTROL HISTORY (RoB) (FRONT RADAR SENSOR SYSTEM)

NOTICE:

By performing this procedure, all stored Vehicle Control History will be cleared.

(a) According to the display on the GTS, clear the Vehicle Control History (RoB).

Body Electrical > Front Radar Sensor > Utility

Tester Display
Toyota Prius Vehicle Control History (RoB)

CHECK VEHICLE CONTROL HISTORY (AIRBAG SYSTEM)

(a) Part of the control history can be confirmed using the Vehicle Control History.

Click here

Front Radar Sensor Optical Axis Misalignment Malfunction (C1A1100)

DESCRIPTION

The millimeter wave radar sensor assembly performs self-diagnosis to check for misalignment of its beam axis. If misalignment is detected, the millimeter wave radar sensor assembly stores DTC C1A1100.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	DTC Output from	Priority
C1A1100	Front Radar Sensor Optical Axis Misalignment Malfunction	When the ignition switch is ON, the millimeter wave radar sensor assembly detects beam axis misalignment	Millimeter wave radar sensor assembly beam axis adjustment Millimeter wave radar sensor assembly	Front Radar Sensor	A

CAUTION / NOTICE / HINT

NOTICE:

When replacing the millimeter wave radar sensor assembly, always replace it with a new one. If a millimeter wave radar sensor assembly which was installed to another Toyota Prius vehicle is used, the information stored in the millimeter wave radar sensor assembly will not match the information from the vehicle and a DTC may be stored.
When the millimeter wave radar sensor assembly has been replaced with a new one, it is necessary to perform millimeter wave radar sensor assembly beam axis alignment and to clear the Toyota Prius vehicle control history. Before performing the Driving Adjustment, make sure to read Before Starting Driving Adjustment.
HINT:

Beam axis alignment of the millimeter wave radar sensor assembly can be performed using either Triangle Target, Flat Surface Target or Driving Adjustment.

Triangle Target: Click here

Flat Surface Target: Click here

Driving Adjustment: Click here

PROCEDURE

1.	ADJUST MILLIMETER WAVE RADAR SENSOR ASSEMBLY

(a) Perform millimeter wave radar sensor assembly beam axis adjustment.

HINT:

Beam axis alignment of the millimeter wave radar sensor assembly can be performed using either Triangle Target, Flat Surface Target or Driving Adjustment.

Triangle Target: Click here

Flat Surface Target: Click here

Driving Adjustment: Click here

CLEAR DTC

(a) Clear the DTCs.

Body Electrical > Front Radar Sensor > Clear DTCs

3.	CHECK FOR DTCs

Pre-procedure1

(a) Turn the ignition switch off.

(b) Turn the ignition switch to ON.

HINT:

If the detection conditions are not met, the system cannot detect the malfunction.

Procedure1

(d) Check for DTCs.

Body Electrical > Front Radar Sensor > Trouble Codes

Result	Proceed to
C1A1100 is not output	A
C1A1100 is output	B

Post-procedure1

(e) None

END

REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY

Main Microcomputer in Front Radar Sensor System Internal Failure (C1A8C04,C1A8C46,C1A8D1C,C1A9000)

DESCRIPTION

When an internal malfunction is detected in the millimeter wave radar sensor assembly, a DTC is stored.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	DTC Output from	Priority
C1A8C04	Main Microcomputer in Front Radar Sensor System Internal Failure	When the ignition switch is ON, a millimeter wave radar sensor assembly internal malfunction is detected	Millimeter wave radar sensor assembly	Front Radar Sensor	A
C1A8C46	Main Microcomputer in Front Radar Sensor Calibration/Parameter Memory Failure	When the ignition switch is ON, the millimeter wave radar sensor assembly detects an internal memory malfunction	Millimeter wave radar sensor assembly	Front Radar Sensor	A
C1A8D1C	Power Supply Circuit in Front Radar Sensor Circuit Voltage Out of Range	When the ignition switch is ON, the millimeter wave radar sensor assembly detects a power source circuit malfunction	Millimeter wave radar sensor assembly	Front Radar Sensor	A
C1A9000	Malfunction of Millimeter-wave Circuit in Front Radar Sensor	When the ignition switch is ON, the millimeter wave radar sensor assembly detects an internal millimeter wave circuit malfunction	Millimeter wave radar sensor assembly	Front Radar Sensor	A

CAUTION / NOTICE / HINT

NOTICE:

When replacing the millimeter wave radar sensor assembly, always replace it with a new one. If a millimeter wave radar sensor assembly which was installed to another Toyota Prius vehicle is used, the information stored in the millimeter wave radar sensor assembly will not match the information from the vehicle and a DTC may be stored.
When the millimeter wave radar sensor assembly has been replaced with a new one, it is necessary to perform millimeter wave radar sensor assembly beam axis alignment and to clear the Toyota Prius vehicle control history. Before performing the Driving Adjustment, make sure to read Before Starting Driving Adjustment.
HINT:

Beam axis alignment of the millimeter wave radar sensor assembly can be performed using either Triangle Target, Flat Surface Target or Driving Adjustment.

Triangle Target: Click here

Flat Surface Target: Click here

Driving Adjustment: Click here

PROCEDURE

1.	REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY

HINT:

Click here

END

Lost Communication with Cruise Control Module Missing Message (U010487)

DESCRIPTION

The millimeter wave radar sensor assembly communicates with the forward recognition camera via CAN communication.

If a communication error is detected between the forward recognition camera and millimeter wave radar sensor assembly, the millimeter wave radar sensor assembly stores this DTC.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	DTC Output from	Priority
U010487	Lost Communication with Cruise Control Module Missing Message	Detection condition: Ignition switch ON Malfunction status: Communication malfunction with the forward recognition camera is detected Malfunction duration: 10 seconds or more	Front camera system Harness or connector Forward recognition camera Millimeter wave radar sensor assembly	Front Radar Sensor	B

HINT:

If the DTCs are output simultaneously, the inspection area can be narrowed down.

w/ Advanced Park

Pattern	DTC output part name (Display on GTS)				Suspected Area (Malfunction Status)
	Millimeter Wave Radar Sensor Assembly	Forward Recognition Camera	Clearance warning ECU assembly	Parking assist ECU
	Front Radar Sensor	Front Recognition Camera	Clearance Warning	Circumference Monitoring Camera Control Module
	U010487	U023587	U117987	U11B687
○: DTC is output -: DTC is not output
Pattern 1	○	○	○	○	Connector (Poor connector)
					Harness or connector (Open or short)
					Millimeter wave radar sensor assembly (Internal malfunction)
					Clearance warning ECU assembly (Internal malfunction)
					Parking assist ECU (Internal malfunction)
					Forward recognition camera (Internal malfunction)
Pattern 2	○	-	-	-	Connector (Poor connector)
					Harness or connector (Open)
					Millimeter wave radar sensor assembly (Internal malfunction)
					Forward recognition camera (Internal malfunction)

w/o Advanced Park

Pattern	DTC output part name (Display on GTS)		Suspected Area (Malfunction Status)
	Millimeter Wave Radar Sensor Assembly	Forward Recognition Camera
	Front Radar Sensor	Front Recognition Camera
	U010487	U023587
○: DTC is output -: DTC is not output
Pattern 1	○	○	Connector (Poor connector)
			Harness or connector (Open or short)
			Millimeter wave radar sensor assembly (Internal malfunction)
			Forward recognition camera (Internal malfunction)
Pattern 2	○	-	Connector (Poor connector)
			Harness or connector (Open)
			Millimeter wave radar sensor assembly (Internal malfunction)
			Forward recognition camera (Internal malfunction)

WIRING DIAGRAM

w/ Advanced Park

w/o Advanced Park

CAUTION / NOTICE / HINT

NOTICE:

When replacing the millimeter wave radar sensor assembly, always replace it with a new one. If a millimeter wave radar sensor assembly which was installed to another Toyota Prius vehicle is used, the information stored in the millimeter wave radar sensor assembly will not match the information from the vehicle and a DTC may be stored.
When the millimeter wave radar sensor assembly has been replaced with a new one, it is necessary to perform millimeter wave radar sensor assembly beam axis alignment and to clear the Toyota Prius vehicle control history. Before performing the Driving Adjustment, make sure to read Before Starting Driving Adjustment.
HINT:

Beam axis alignment of the millimeter wave radar sensor assembly can be performed using either Triangle Target, Flat Surface Target or Driving Adjustment.

Triangle Target: Click here

Flat Surface Target: Click here

Driving Adjustment: Click here
When replacing the forward recognition camera, always replace it with a new one. If a forward recognition camera which was installed to another Toyota Prius vehicle is used, the information stored in the forward recognition camera will not match the information from the vehicle and a DTC may be stored.
When the forward recognition camera has been replaced with a new one, make sure to clear all stored vehicle control history of each system and the forward recognition camera beam axis alignment data.
HINT:

Forward recognition camera beam axis alignment can be performed by using "One Time Recognition", "Driving Adjustment" or "Camera Axis Adjustment Value Write".

One Time Recognition: Click here

Driving Adjustment: Click here

Camera Axis Adjustment Value Write: Click here
If the forward recognition camera has been replaced with a new one, make sure to perform Software Version Confirmation.
Click here
After the ignition switch is turned off, there may be a waiting time before disconnecting the negative (-) auxiliary battery terminal.
Click here

HINT:

When disconnecting and reconnecting the auxiliary battery, there is an automatic learning function that completes learning when the respective system is used.

Click here

PROCEDURE

1.	CONFIRM MODEL

(a) Choose the model to be inspected.

Result	Proceed to
w/ Advanced Park	A
w/o Advanced Park	B

GO TO STEP 8

2.	CHECK FOR DTCs

(a) Read each DTC and check the diagnosis pattern using the table below.

Body Electrical > Front Radar Sensor > Trouble Codes Chassis > Front Recognition Camera > Trouble Codes Body Electrical > Clearance Warning > Trouble Codes Chassis > Circumference Monitoring Camera Control Module > Trouble Codes

Pattern

DTC output part name

(Display on GTS)

Front Radar Sensor

Front Recognition Camera

Clearance Warning

Circumference Monitoring Camera Control Module

Pattern 1

U010487

U023587

U117987

U11B687

Pattern 2

U010487

Result	Proceed to
Pattern 1	A
Pattern 2	B

GO TO FRONT CAMERA SYSTEM

3.	CHECK CONNECTION OF CONNECTORS

(a) Check that the connectors are properly connected to the forward recognition camera and millimeter wave radar sensor assembly.

OK:

The connectors are properly connected

CONNECT CONNECTORS PROPERLY

CLEAR DTC

(a) Read each DTC and check the diagnosis pattern using the table below.

Body Electrical > Front Radar Sensor > Clear DTCs

5.	CHECK FOR DTCs

Pre-procedure1

(a) Turn the ignition switch off.

(b) Turn the ignition switch to ON.

HINT:

If the detection conditions are not met, the system cannot detect the malfunction.

Procedure1

(d) Check for DTCs.

Body Electrical > Front Radar Sensor > Trouble Codes

Result	Proceed to
U010487 is not output	A
U010487 is output	B

Post-procedure1

(e) None

END

6.	CHECK CAN MAIN WIRE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

Pre-procedure1

(a) Disconnect the cable from the negative (-) auxiliary battery terminal.

(b) Disconnect the A21 millimeter wave radar sensor assembly connector.

Procedure1

Standard Resistance:

Click Location & Routing(A21) Click Connector(A21)

Tester Connection	Condition	Specified Condition	Result
A21-8 (CA1P) - A21-7 (CA1N)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω	Ω

Post-procedure1

(d) None

REPAIR OR REPLACE CAN BUS HARNESS OR CONNECTOR

7.	CHECK FORWARD RECOGNITION CAMERA

Pre-procedure1

(a) Disconnect the A21 millimeter wave radar sensor assembly connector.

Procedure1

(b) Using an oscilloscope, check the waveform.

OK:

Click Location & Routing(A21) Click Connector(A21)

Tester Connection	Condition	Tool Setting	Specified Condition
A21-8 (CA1P) - A21-7 (CA1N)	Ignition switch ON	1V/DIV., 100μs./DIV.	Pulse generation

Post-procedure1

REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY

REPLACE FORWARD RECOGNITION CAMERA

8.	CHECK FOR DTCs

(a) Read each DTC and check the diagnosis pattern using the table below.

Body Electrical > Front Radar Sensor > Trouble Codes Chassis > Front Recognition Camera > Trouble Codes

Pattern

DTC output part name

(Display on GTS)

Front Radar Sensor

Front Recognition Camera

Pattern 1

U010487

U023587

Pattern 2

U010487

Result	Proceed to
Pattern 1	A
Pattern 2	B

GO TO FRONT CAMERA SYSTEM

9.	CHECK CONNECTION OF CONNECTORS

(a) Check that the connectors are properly connected to the forward recognition camera and millimeter wave radar sensor assembly.

OK:

The connectors are properly connected

CONNECT CONNECTORS PROPERLY

10.

CLEAR DTC

(a) Read each DTC and check the diagnosis pattern using the table below.

Body Electrical > Front Radar Sensor > Clear DTCs

11.	CHECK FOR DTCs

Pre-procedure1

(a) Turn the ignition switch off.

(b) Turn the ignition switch to ON.

HINT:

If the detection conditions are not met, the system cannot detect the malfunction.

Procedure1

(d) Check for DTCs.

Body Electrical > Front Radar Sensor > Trouble Codes

Result	Proceed to
U010487 is not output	A
U010487 is output	B

Post-procedure1

(e) None

END

12.	CHECK CAN MAIN WIRE (MILLIMETER WAVE RADAR SENSOR ASSEMBLY)

Pre-procedure1

(a) Disconnect the cable from the negative (-) auxiliary battery terminal.

(b) Disconnect the A21 millimeter wave radar sensor assembly connector.

Procedure1

Standard Resistance:

Click Location & Routing(A21) Click Connector(A21)

Tester Connection	Condition	Specified Condition	Result
A21-8 (CA1P) - A21-7 (CA1N)	Cable disconnected from negative (-) auxiliary battery terminal	108 to 132 Ω	Ω

Post-procedure1

(d) None

REPAIR OR REPLACE CAN BUS HARNESS OR CONNECTOR

13.	CHECK FORWARD RECOGNITION CAMERA

Pre-procedure1

(a) Disconnect the A21 millimeter wave radar sensor assembly connector.

Procedure1

(b) Using an oscilloscope, check the waveform.

OK:

Click Location & Routing(A21) Click Connector(A21)

Tester Connection	Condition	Tool Setting	Specified Condition
A21-8 (CA1P) - A21-7 (CA1N)	Ignition switch ON	1V/DIV., 100μs./DIV.	Pulse generation

Post-procedure1

REPLACE MILLIMETER WAVE RADAR SENSOR ASSEMBLY

REPLACE FORWARD RECOGNITION CAMERA

Software Incompatibility with Image Processing Module "A" Not Programmed (U130C51,U130C57)

DESCRIPTION

The millimeter wave radar sensor assembly receives the vehicle information from the forward recognition camera via CAN communication line. When the millimeter wave radar sensor assembly cannot confirm the vehicle information using the vehicle information sent from the forward recognition camera, the millimeter wave radar sensor assembly stores DTC U130C51.
The millimeter wave radar sensor assembly receives the Toyota Prius vehicle information from the forward recognition camera via CAN communication line. When the vehicle information value sent from the forward recognition camera does not match that stored by the millimeter wave radar sensor assembly, the millimeter wave radar sensor assembly stores DTC U130C57.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	DTC Output from	Priority
U130C51	Software Incompatibility with Image Processing Module "A" Not Programmed	When the millimeter wave radar sensor assembly cannot confirm the Toyota Prius vehicle information using the vehicle information sent from the millimeter wave radar sensor assembly	Millimeter wave radar sensor assembly	Front Radar Sensor	B
U130C57	Software Incompatibility with Image Processing Module "A" Invalid/Incompatible Software Component	When the Toyota Prius vehicle information value sent from the forward recognition camera does not match that stored by the millimeter wave radar sensor assembly	Millimeter wave radar sensor assembly	Front Radar Sensor	B

CAUTION / NOTICE / HINT

NOTICE:

When replacing the millimeter wave radar sensor assembly, always replace it with a new one. If a millimeter wave radar sensor assembly which was installed to another Toyota Prius vehicle is used, the information stored in the millimeter wave radar sensor assembly will not match the information from the vehicle and a DTC may be stored.
When the millimeter wave radar sensor assembly has been replaced with a new one, it is necessary to perform millimeter wave radar sensor assembly beam axis alignment and to clear the Toyota Prius vehicle control history. Before performing the Driving Adjustment, make sure to read Before Starting Driving Adjustment.
HINT:

Beam axis alignment of the millimeter wave radar sensor assembly can be performed using either Triangle Target, Flat Surface Target or Driving Adjustment.

Triangle Target: Click here

Flat Surface Target: Click here

Driving Adjustment: Click here