PRE-CRASH SAFETY SYSTEM, Diagnostic DTC:U0100, U0125, U0126, U0129, U0235, U023A, U1002

DTC Code	DTC Name
U0100	Lost Communication with ECM / PCM "A"
U0125	Lost Communication with Yaw Rate Sensor Module
U0126	Lost Communication With Steering Angle Sensor Module
U0129	Lost Communication with Brake System Control Module
U0235	Lost Communication with Cruise Control Front Distance Range Sensor
U023A	Lost Communication with Front Camera Module
U1002	Lost Communication with Gateway Module

DESCRIPTION

The driving support ECU assembly uses the millimeter wave radar sensor assembly to detect obstacles in front of the vehicle. Based on this information, the driving support ECU assembly sends pre-crash safety control operation signals. These DTCs are stored when a communication malfunction occurs between the sensors and ECUs that detect crashes, or between ECUs that perform the pre-collision control.
The driving support ECU assembly, millimeter wave radar sensor assembly and forward recognition camera are connected via CAN communication lines. If communication with the millimeter wave radar sensor assembly or forward recognition camera stops, the driving support ECU assembly will store DTC U1002.

DTC No.	DTC Detection Condition	Trouble Area
U0100	When the engine switch is on (IG), a communication error between the ECM and the driving support ECU assembly is detected for approximately 5 seconds.	CAN communication system Driving support ECU assembly ECM Wire harness or connector
U0125	When the engine switch is on (IG), a communication error between the airbag sensor assembly (yaw rate sensor) and the driving support ECU is detected for approximately 1 second.	CAN communication system Airbag sensor assembly (yaw rate and acceleration sensor) Driving support ECU assembly Wire harness or connector
U0126	When the engine switch is on (IG), a communication error between the steering sensor and the driving support ECU assembly is detected for approximately 4 seconds.	CAN communication system steering sensor Driving support ECU assembly Wire harness or connector
U0129	When the engine switch is on (IG), a communication error between the brake actuator assembly (skid control ECU) and the driving support ECU assembly is detected for approximately 3 seconds.	CAN communication system Brake actuator assembly (skid control ECU) Driving support ECU assembly Wire harness or connector
U0235	When the engine switch is on (IG), a communication error between the millimeter wave radar sensor assembly and the driving support ECU assembly is detected for approximately 1 second.	CAN communication system Millimeter wave radar sensor assembly Driving support ECU assembly Wire harness or connector
U023A	When the engine switch is on (IG), a communication error between the forward recognition camera and driving support ECU is detected for approximately 2 seconds.	CAN communication system Forward recognition camera Driving support ECU assembly Wire harness or connector
U1002	When the engine switch is on (IG), a communication error between the millimeter radar sensor and driving support ECU assembly or the forward recognition camera and driving support ECU assembly is detected for 2 seconds or more.	CAN communication system Millimeter wave radar sensor assembly Forward recognition camera Driving support ECU assembly Wire harness or connector

PROCEDURE

CHECK DTC OUTPUT (PRE-CRASH SAFETY SYSTEM)

Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Body Electrical / Pre-Crash 2 / Trouble Codes.
Clear the DTCs Click here.
Make sure that the DTC detection conditions are met.

Tech Tips

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

Check for DTCs Click here.

Result
Result	Proceed to
DTC U0100, U0125, U126, U0129, U0235, U023A and U1002 are not output	A
DTC U0100, U0125, U126, U0129, U0235, U023A or U1002 are output	B

USE SIMULATION METHOD TO CHECK Click here

GO TO CAN COMMUNICATION SYSTEM Click here