C1378

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1378/44: Capacitor Communication Malfunction

DTC C1378/44 - Capacitor Communication Malfunction

DESCRIPTION

The brake control power supply (capacitor) is used as auxiliary power for brake control when battery voltage is low.







WIRING DIAGRAM





INSPECTION PROCEDURE
NOTICE:
When replacing the skid control ECU, perform the following operations:
- Initialization of linear solenoid valve and calibration Programming and Relearning
- Yaw rate and acceleration sensor zero point calibration Programming and Relearning

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (BRAKE CONTROL POWER SUPPLY - BATTERY AND BODY GROUND)




(a) Disconnect the S49 power supply connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:





(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE CONTROL POWER SUPPLY ASSEMBLY)




(a) Disconnect the A19 and A21 ECU connectors.
(b) Disconnect the S49 power supply connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
3. RECONFIRM DTC
(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(b) Turn the power switch ON (IG).
(c) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.
HINT: Reinstall the sensor, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.

Result





B -- USE SIMULATION METHOD TO CHECK
A -- Continue to next step.
4. CHECK FREEZE FRAME DATA
(a) Check the information code from the "FREEZE FRAME DATA" memorized when the DTC (C1378/44) is stored Freeze Frame Data.

Result





B -- REPLACE BRAKE CONTROL POWER SUPPLY ASSEMBLY
A -- REPLACE SKID CONTROL ECU