DTC    C0278    Open in ABS Solenoid Relay Circuit

DTC    C0279    Short in ABS Solenoid Relay Circuit

for Preparation Click here


DESCRIPTION

The ABS solenoid relay supplies power to the ABS solenoid and TRC solenoid.
The solenoid relay is turned on 1.5 seconds after the ignition switch is turned to ON, and is turned off if an open or short in the solenoid is detected by the self diagnosis performed when the engine starts running.
The ABS solenoid relay is housed in the skid control ECU in the actuator assembly.
On vehicles equipped with the Stop and Start System, DTC may be output if there is a significant difference between IG power source voltage and backup boost converter power source voltage when the stop and start system is cranking the engine during restarting.

DTC Code
DTC Detection Condition
Trouble Area
C0278
When either of the following is detected:
  1. Both of the following conditions continue for 0.22 seconds or more.
    1. The IG1 terminal voltage is 9.5 V or more.
    2. The solenoid relay contact is open when the relay is ON.
  2. Both of the following conditions continue for 0.22 seconds or more.
    1. The IG1 terminal voltage becomes lower than 9.5 V or less when the relay is turned on.
    2. The relay contact remains open.
  1. ABS No. 2 fuse
  2. ABS solenoid relay circuit
  3. Brake actuator assembly (ABS solenoid relay)
C0279
Immediately after the ignition switch is turned to ON, the solenoid relay contact is closed for 4 seconds when the relay is turned off.
  1. ABS solenoid relay circuit
  2. Brake actuator assembly (ABS solenoid relay)

WIRING DIAGRAM

Refer to DTCs C0226, C0236, C0246, C0256 and C1225 (Click here).

INSPECTION PROCEDURE

NOTICE:
  1. When replacing the brake actuator assembly, perform zero point calibration (Click here).
  2. Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT:
When C1241 is output together with C0278 and/or C0279, inspect and repair the trouble areas indicated by C1241 first (Click here).

1.INSPECT SKID CONTROL ECU (+BS TERMINAL)

  1. Turn the ignition switch off.

  1. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

  1. Check the connector case and terminals for deformation and corrosion.

    Standard condition:
    No deformation or corrosion.



    E175972E13

  1. Disconnect the A16 or A17 skid control ECU connector.
    Text in Illustration 
    *A
    		for LHD
    *B
    		for RHD
    *1
    		Front view of wire harness connector
    (to Skid Control ECU)

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

    Standard Voltage:
    for LHD 
    Tester Connection
    		Condition
    		Specified Condition
    A16-12 (+BS) - Body ground
    		Always
    		11 to 14 V
    for RHD 
    Tester Connection
    		Condition
    		Specified Condition
    A17-12 (+BS) - Body ground
    		Always
    		11 to 14 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (+BS CIRCUIT)
OK


2.INSPECT SKID CONTROL ECU (GND TERMINAL)


    E175972E14

  1. Measure the resistance according to the value(s) in the table below.
    Text in Illustration 
    *A
    		for LHD
    *B
    		for RHD
    *1
    		Front view of wire harness connector
    (to Skid Control ECU)

    Standard Resistance:
    for LHD 
    Tester Connection
    		Condition
    		Specified Condition
    A16-1 (GND1) - Body ground
    		Always
    		Below 1 Ω
    for RHD 
    Tester Connection
    		Condition
    		Specified Condition
    A17-1 (GND1) - Body ground
    		Always
    		Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK


3.RECONFIRM DTC

HINT:
This code is detected when a problem is identified in the brake actuator assembly.
The solenoid circuit is in the brake actuator assembly.
Therefore, solenoid circuit inspection and solenoid unit inspection cannot be performed. Be sure to check if the DTC is output before replacing the brake actuator assembly.

  1. Reconnect the skid control ECU connector.

  1. Clear the DTC (Click here).

  1. Start the engine.

  1. Drive the vehicle at a speed of 20 km/h (12 mph) or more for 30 seconds or more.

  1. Check if the same DTC is recorded (Click here).
    Result 
    Result
    		Proceed to
    DTC not output
    		A
    DTC output
    		B

    HINT:
    1. If a speed signal of 6 km/h (4 mph) or more is input to the skid control ECU, with the ignition switch ON and the stop light switch off, the ECU performs self diagnosis of the motor and solenoid circuits.
    2. If the normal system code is output (the trouble code is not output), slightly jiggle the connectors, wire harnesses, and fuses of the brake actuator assembly. Make sure that no DTCs are output.
    3. If any DTCs are output while jiggling a connector or wire harness of the brake actuator assembly (skid control ECU), inspect and repair the connector or wire harness.
    4. The DTCs were probably output due to a bad connection of the connector terminal.



B
REPLACE BRAKE ACTUATOR ASSEMBLY (Click here)
A

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