Dtc C0278 Open In Abs Solenoid Relay Circuit

Brake. Yaris. Ncp93, 131
Brake Control Dynamic Control Systems. Yaris. Ncp93, 131

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK HARNESS AND CONNECTOR (+BS TERMINAL)

CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)

RECONFIRM DTC

DTC C0278 Open in ABS Solenoid Relay Circuit

DTC C0279 Short in ABS Solenoid Relay Circuit


DESCRIPTION

The ABS solenoid relay supplies power to the ABS 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.

DTC NO.
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. ABS2/VSC2 fuse
  2. Harness or connector
  3. Brake actuator assembly
C0279
Immediately after the ignition switch is turned to ON, the solenoid relay contact is closed for 4.5 seconds when the relay is turned off.
Brake actuator assembly

WIRING DIAGRAM

Refer to DTCs C0226, C0236, C0246 and C0256 (YARIS_NCP93 RM000000XI80AXX_02.html).

INSPECTION PROCEDURE

NOTICE:
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 (YARIS_NCP93 RM000000XW60BIX.html).
1.CHECK HARNESS AND CONNECTOR (+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. Disconnect the A15 brake actuator assembly (skid control ECU) connector.



    Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan). Dtc C0278 Open In Abs Solenoid Relay Circuit

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

    OK:
    No deformation or corrosion.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A15-12 (+BS) - Body ground
    		Always
    		11 to 14 V
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Brake Actuator Assembly (Skid Control ECU))


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


2.CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)


    Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan). Dtc C0278 Open In Abs Solenoid Relay Circuit

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    A15-1 (GND1) - Body ground
    		Always
    		Below 1 Ω
    Text in Illustration
    *a
    		Front view of wire harness connector
    (to Brake Actuator Assembly (Skid Control ECU))

  1. Reconnect the A15 brake actuator assembly (skid control ECU) connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)
OK


3.RECONFIRM DTC
HINT:
These codes are detected when a problem is determined in the brake actuator assembly (skid control ECU).
The solenoid circuits are in the brake actuator assembly (skid control ECU).
Therefore, solenoid circuit inspection and solenoid unit inspection cannot be performed. Be sure to check if any DTCs are output before replacing the brake actuator assembly (skid control ECU).

  1. Clear the DTC (YARIS_NCP93 RM000000XHV0BPX.html).

  1. Start the engine.

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

  1. Check if the same DTC is recorded (YARIS_NCP93 RM000000XHV0BPX.html).

    Result
    Result
    		Proceed to
    DTC is not output
    		A
    DTC is output
    		B
HINT:
  1. If a speed signal of 6 km/h (4 mph) or more is input to the brake actuator assembly (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 harness, and fuses of the brake actuator assembly (skid control ECU). Make sure that no DTCs are output.
  3. If any DTCs are output while jiggling a connector or wire harness from 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 (YARIS_NCP93 RM000001BXP02FX.html)
A

CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) (YARIS_NCP93 RM000000UZ309WX.html)