Diagnostic trouble code C0278 C0279 Land Cruiser

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT ABS2 FUSE

INSPECT SKID CONTROL ECU (+BS TERMINAL)

INSPECT SKID CONTROL ECU (GND TERMINAL)

RECONFIRM DTC

DTC C0278/11 Open or Short Circuit in ABS Solenoid Relay Circuit

DTC C0279/12 Short to B+ in ABS Solenoid Relay Circuit

Description

The solenoid relay is built into the master cylinder solenoid.

This relay supplies power to each solenoid. If the initial check is OK, after the ignition switch is turned to ON, the relay turns on.

DTC Code DTC Detection Condition Trouble Area
C0278/11 When either of the following conditions is detected:
  1. Both of the following conditions continue for at least 0.2 seconds.
    1. IG voltage is between 9.5 V and 17 V.
    2. The relay contact is open when the relay is on.
  2. Both of the following conditions continue for at least 0.2 seconds.
    1. IG voltage is 9.5 V or less when the relay is on.
    2. The relay contact remains open.
  1. ABS2 fuse
  2. Solenoid relay
  3. Harness or connector
  4. Master cylinder solenoid (Skid control ECU)
C0279/12 The following condition continues for at least 0.2 seconds.
  1. The relay contact is closed immediately after turning the ignition switch to ON when the relay is off.
  1. ABS2 fuse
  2. Solenoid relay
  3. Harness or connector
  4. Master cylinder solenoid (Skid control ECU)

Wiring diagram

Diagnostic trouble code C0278 C0279 Land Cruiser. Wiring diagram

Inspection procedure

NOTICE:

When replacing the master cylinder solenoid, perform zero point calibration .

1.INSPECT ABS2 FUSE

Diagnostic trouble code C0278 C0279 Land Cruiser. Remove the ABS2 fuse from the engine room relay block.

  1. Remove the ABS2 fuse from the engine room relay block.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:

    Tester Connection Condition Specified Condition
    ABS2 fuse Always Below 1 ?
  NG  
REPLACE ABS2 FUSE
 
OK  
   

2.INSPECT SKID CONTROL ECU (+BS TERMINAL)

Diagnostic trouble code C0278 C0279 Land Cruiser. Install the ABS2 fuse.

  1. Install the ABS2 fuse.

  1. Disconnect the A24 skid control ECU connector.

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:

    Tester Connection Condition Specified Condition
    A24-31 (+BS) - Body ground Always 11 to 14 V
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

3.INSPECT SKID CONTROL ECU (GND TERMINAL)

Diagnostic trouble code C0278 C0279 Land Cruiser. Disconnect the A24 and A25 skid control ECU connectors.

  1. Disconnect the A24 and A25 skid control ECU connectors.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:

    Tester Connection Condition Specified Condition
    A24-1 (GND1) - Body ground Always Below 1 ?
    A24-32 (GND2) - Body ground Always Below 1 ?
    A25-4 (GND3) - Body ground Always Below 1 ?
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

4.RECONFIRM DTC

HINT:

These codes are stored when a problem is detected in the master cylinder solenoid.

The ABS solenoid relay is in the master cylinder solenoid.

Therefore, solenoid relay circuit inspection and relay unit inspection cannot be performed. Be sure to check if any DTC is output before replacing the master cylinder solenoid.

  1. Clear the DTCs .

  1. Drive the vehicle at a speed of approximately 32 km/h (20 mph) or more for 60 seconds or more.

  1. Check if the same DTCs are output .

    HINT:

    Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

    Result
    Result Proceed to
    DTC is not output A
    DTC is output LHD B
    RHD C
  B  
REPLACE MASTER CYLINDER SOLENOID
 
  C  
REPLACE MASTER CYLINDER SOLENOID
 
A  
   
USE SIMULATION METHOD TO CHECK