Toyota Tundra Service Manual: Control Module Communication Bus "A" Off (U0073,U0123,U0129,U0155)

Toyota Tundra Service Manual / Brake / Brake Control / Dynamic Control Systems / Trailer Brake Control System / Control Module Communication Bus "A" Off (U0073,U0123,U0129,U0155)

DESCRIPTION

The trailer brake control ECU (brake control with bracket relay) receives signals from the skid control ECU (brake actuator assembly), yaw rate and acceleration sensor (airbag sensor assembly) and combination meter assembly via CAN communication.

DTC No.	Detection Item	INF Code	DTC Detection Condition	Trouble Area
U0073	Control Module Communication Bus "A" Off	-	Bus off condition continues for 1 second or more	CAN communication system
U0123	Lost Communication with Yaw Rate Sensor Module	-	With a vehicle speed of 6 km/h (4 mph), the system is continuously unable to receive data from the yaw rate and acceleration sensor (airbag sensor assembly) for 1 second or more	CAN communication system Trailer brake control ECU (Brake control with bracket relay) Yaw rate and acceleration sensor (airbag sensor assembly)
U0129	Lost Communication with Brake System Control Module	-	The skid control ECU (brake actuator assembly) is continuously unable to receive data from the brake actuator assembly (skid control ECU) for 1 second or more.	CAN communication system Trailer brake control ECU (Brake control with bracket relay) Skid control ECU (Brake actuator assembly)
U0155	Lost Communication With Instrument Panel Cluster (IPC) Control Module	-	With a vehicle speed of 6 km/h (4 mph), the system is continuously unable to receive data from the combination meter assembly for 5 seconds or more	CAN communication system Trailer brake control ECU (Brake control with bracket relay) Combination meter assembly

PROCEDURE

CHECK DTC

(a) Clear the DTCs.

Click here

(b) Turn the ignition switch off.

(d) Check if the same DTC is output.

Click here

HINT:

If a CAN communication malfunction DTC and a related sensor malfunction DTC are output at the same time, the CAN communication malfunction must be repaired before troubleshooting the sensor malfunction DTC.

Result	Proceed to
CAN communication system DTCs are output.	A
DTCs are not output.	B

INSPECT CAN COMMUNICATION SYSTEM

USE SIMULATION METHOD TO CHECK

Terminals Of Ecu

Vehicle Stability Control System

See More:

Toyota Tundra Owners Manual > Steps to take in an emergency: If a warning light turns on or a warning buzzer sounds
Calmly perform the following actions if any of the warning lights comes on or flashes. If a light comes on or flashes, but then goes off, this does not necessarily indicate a malfunction in the system. However, if this continues to occur, have the vehicle inspected by your Toyota dealer. Warning li ...