ECM Communication Circuit Malfunction

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C1203/53: ECM Communication Circuit Malfunction

DTC C1203/53 - ECM Communication Circuit Malfunction

DESCRIPTION

The circuit is used to send TRAC & VSC control information from the skid control ECU (TRC+, TRC-) to the translate ECU, and engine control information from the translate ECU to the skid control ECU (ENG+, ENG-).






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK WIRE HARNESS (SKID CONTROL ECU - TRANSLATE ECU)




(a) Disconnect the S5 and T28 ECU connectors.
(b) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
2. CHECK ECU COMMUNICATION (SKID CONTROL ECU - TRANSLATE ECU)




(a) Remove the skid control ECU but do not disconnect the connectors.
(b) Connect an oscilloscope to terminals 11 (ENG+) and 18 (ENG-) or 20 (TRC+) and 13 (TRC-) of the S5 skid control ECU.
(c) Start the engine, and check the signal waveform.
OK:
Waveform is output as shown in illustration.
NG -- REPLACE SKID CONTROL ECU
OK -- REPLACE TRANSLATE ECU