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Home >> Toyota >> 2025 >> 4Runner TRD Pro >> Repair and Diagnosis (Single Page) >> General Information >> Towing >> Trailer Brake Control System - Diagnostic Codes & Symptom Tests >> Trailer Brake Control System >> DTC U0076-88: Control Module Communication Bus "D" Off Bus Off; DTC U0077-88: Control Module Communication Bus "E" Off Bus Off; DTC U0078-88: Control Module Communication Bus "F" Off Bus Off; DTC U0129-87: Lost Communication with Brake System Control Module "A" Missing Message; DTC U0155-87: Lost Communication with Instrument Panel Cluster (IPC) Control Module Missing Message; DTC U1170-87: Lost Communication with Brake System Control Module (ch2) Missing Message; DTC U1171-87: Lost Communication with Brake System Control Module (ch3) Missing Message [12/2024 - ] >> Description
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DTC U0076-88: Control Module Communication Bus "D" Off Bus Off; DTC U0077-88: Control Module Communication Bus "E" Off Bus Off; DTC U0078-88: Control Module Communication Bus "F" Off Bus Off; DTC U0129-87: Lost Communication with Brake System Control Module "A" Missing Message; DTC U0155-87: Lost Communication with Instrument Panel Cluster (IPC) Control Module Missing Message; DTC U1170-87: Lost Communication with Brake System Control Module (ch2) Missing Message; DTC U1171-87: Lost Communication with Brake System Control Module (ch3) Missing Message [12/2024 - ]: Description

The following DTCs are output when there is a communication malfunction between a sensor or ECU.

DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from Priority
U0076-88 Control Module Communication Bus "D" Off Bus Off Bus off condition continues for 1 second or more.*1 CAN communication system Trailer Brake Controller B
U0077-88 Control Module Communication Bus "E" Off Bus Off Bus off condition continues for 1 second or more.*2 CAN communication system Trailer Brake Controller B
U0078-88 Control Module Communication Bus "F" Off Bus Off Bus off condition continues for 1 second or more CAN communication system Trailer Brake Controller B
U0129-87 Lost Communication with Brake System Control Module "A" Missing Message
  • The trailer brake control ECU (brake control with bracket relay) is continuously unable to receive data from the skid control ECU (brake actuator assembly) for 1 second or more.*1
  • The trailer brake control ECU (brake control with bracket relay) is continuously unable to receive data from the No. 2 skid control ECU (brake actuator assembly) for 1 second or more.*2
  • CAN communication system
  • Trailer brake control ECU (brake control with bracket relay)
  • Skid control ECU (brake actuator assembly)*1
  • No. 2 Skid control ECU (brake actuator assembly)*2
Trailer Brake Controller B
U0155-87 Lost Communication with Instrument Panel Cluster (IPC) Control Module Missing Message 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
Trailer Brake Controller B
U1170-87 Lost Communication with Brake System Control Module (ch2) Missing Message The trailer brake control ECU (brake control with bracket relay) is continuously unable to receive data from the No. 2 skid control ECU (brake actuator assembly) for 1 second or more.*2
  • CAN communication system
  • Trailer brake control ECU (brake control with bracket relay)
  • No. 2 Skid control ECU (brake actuator assembly)
Trailer Brake Controller B
U1171-87 Lost Communication with Brake System Control Module (ch3) Missing Message The trailer brake control ECU (brake control with bracket relay) is continuously unable to receive data from the skid control ECU (brake actuator assembly) for 1 second or more.*1
  • CAN communication system
  • Trailer brake control ECU (brake control with bracket relay)
  • Skid control ECU (brake actuator assembly)
Trailer Brake Controller B

*1: for Gasoline Model

*2: except Gasoline Model