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Home >> Toyota >> 2021 >> Prius LE >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (8 Of 8) & Circuit Tests >> SFI System >> DTC U0129-87: Lost Communication with Brake System Control Module Missing Message [12/2018 - ] >> Monitor Description
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Monitor Description

The ECM and skid control ECU (brake booster with master cylinder assembly) send and receive signals via CAN communication.

If a communication error occurs between the ECM and skid control ECU (brake booster with master cylinder assembly), the ECM illuminates the MIL and stores this DTC.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory Note
U0129-87 Lost Communication with Brake System Control Module Missing Message All of the following conditions are met for 4.98 seconds or more (1 trip detection logic):
  • Power switch on (IG)
  • Auxiliary battery voltage is 10 V or higher
  • No communication between ECM and skid control ECU (brake booster with master cylinder assembly)
  • CAN communication system
  • Skid control ECU (brake booster with master cylinder assembly)
  • ECM
Comes on DTC stored
  • SAE Code: U0129
  • DTC for Mexico Models: Does not apply