DTC    C1437    Lost Communication with ECM

for Preparation Click here


DESCRIPTION

The skid control ECU receives signals from the ECM via the CAN communication system.

DTC Code
DTC Detection Condition
Trouble Area
C1437
When the IG1 terminal voltage is 10 V or more and the vehicle speed is 15 km/h (9 mph) or more, data cannot be sent to the ECM for 2 seconds or more.
  1. CAN communication system (Skid control ECU to ECM)
  2. Brake actuator assembly (Skid control ECU)

WIRING DIAGRAM

Refer to DTCs U0073, U0100, U0123, U0124 and U0126 (Click here).

INSPECTION PROCEDURE

NOTICE:
When replacing the brake actuator assembly, perform zero point calibration (Click here).

1.CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)

  1. Using the intelligent tester, check for any momentary interruption in the wire harness and connector corresponding to the DTC (Click here).

    ABS/VSC/TRC 
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    EFI Communication Open
    		EFI communication open detection/ERROR or NORMAL
    		ERROR: Momentary interruption
    NORMAL: Normal
    		-

    OK:
    There are no momentary interruptions.

    HINT:
    Perform the above inspection before removing the sensor and connector.



NG
Go to step 3
OK


2.RECONFIRM DTC

  1. Turn the ignition switch off.

  1. Clear the DTCs (Click here).

  1. Start the engine.

  1. Drive the vehicle at a speed of 15 km/h (9 mph) or more for 10 seconds or more.

  1. Check that no CAN communication system DTC is output (Click here).

  1. Check if the same DTC is recorded (Click here).

    Result:

    Result
    		Proceed to
    DTC (C1437) is not output
    		A
    DTC (C1437) is output
    		B
    DTC (CAN communication system DTC) is output
    		C



B
REPLACE BRAKE ACTUATOR ASSEMBLY (Click here)

C
CHECK CAN COMMUNICATION SYSTEM (Click here)
A

CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) (Click here)  

3.REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL ECU - ECM)

  1. Turn the ignition switch off.

  1. Repair or replace the harness or connector.

  1. Check for any momentary interruption between the skid control ECU and the ECM (Click here).

  1. Check that there is no momentary interruption.


NEXT


4.RECONFIRM DTC

  1. Turn the ignition switch off.

  1. Clear the DTCs (Click here).

  1. Start the engine.

  1. Drive the vehicle at a speed of 15 km/h (9 mph) or more for 10 seconds or more.

  1. Check that no CAN communication system DTC is output (Click here).

  1. Check if the same DTC is recorded (Click here).

    Result:

    Result
    		Proceed to
    DTC (C1437) is not output
    		A
    DTC (C1437) is output
    		B
    DTC (CAN communication system DTC) is output
    		C



B
REPLACE BRAKE ACTUATOR ASSEMBLY (Click here)

C
CHECK CAN COMMUNICATION SYSTEM (Click here)
A

END