Dtc C0278/11 Open In Abs Solenoid Relay Circuit

Lexus IS250 IS220d GSE20 ALE20 - BRAKE CONTROL

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT ABS2 FUSE

INSPECT SKID CONTROL ECU (+BS AND GND TERMINAL)

RECONFIRM DTC

DTC C0278/11 Open in ABS Solenoid Relay Circuit

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

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 engine switch is turned on (IG), and is turned off if an open or short in the solenoid is detected by self diagnosis performed when the vehicle starts running.


The ABS solenoid relay is housed in the skid control ECU in the actuator assembly.


  • HINT:
  • If a speed signal of 4 mph (6 km/h) or more is input to the skid control ECU, with the engine switch on (IG) and the stop light switch off, the ECU performs self diagnosis of the motor and solenoid circuits.
DTC No.DTC Detection ConditionTrouble Area
C0278/11When any of the following (1 or 2) is detected:
All of the following conditions continue for 0.2 seconds or more.
The IG1 terminal voltage is between 9.5 and 17.2 V.
The solenoid relay contact is open when the relay is ON.
All of the following conditions continue for 0.2 seconds or more.
IG1 terminal voltage becomes lower than 9.5 V or less when the relay is turned on.
The relay contact remains open.
ABS2 fuse
ABS solenoid relay
ABS solenoid relay circuit
Brake actuator assembly
C0279/12Immediately after the engine switch is turned on (IG), the solenoid relay contact is closed for 0.2 seconds when the relay is turned off.Brake actuator assembly

WIRING DIAGRAM

Dtc C0278/11 Open In Abs Solenoid Relay Circuit. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

  • NOTICE:
  • When replacing the brake actuator assembly, perform zero point calibration .
1.INSPECT ABS2 FUSE
Dtc C0278/11 Open In Abs Solenoid Relay Circuit. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Remove the ABS2 fuse from the engine room No. 1 R/B.

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

  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    ABS2 (30A) fuseAlwaysBelow 1 Ω
NG
REPLACE ABS2 FUSE
OK
2.INSPECT SKID CONTROL ECU (+BS AND GND TERMINAL)
Dtc C0278/11 Open In Abs Solenoid Relay Circuit. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

Install the ABS2 fuse.

Disconnect the skid control ECU connector.

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

  • Standard voltage:
  • Tester ConnectionConditionSpecified Condition
    A14-31 (+BS) - Body groundAlways10 to 14 V

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

  • Standard resistance:
  • Tester ConnectionConditionSpecified Condition
    A14-32 (GND1) - Body groundAlwaysBelow 1 Ω
    A14-1 (GND2) - Body groundAlwaysBelow 1 Ω
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (+BS OR GND CIRCUIT)
OK
3.RECONFIRM DTC

Reconnect the skid control ECU connector.

Clear the DTC .

Start the engine.

Drive the vehicle at the speed of 4 mph (6 km/h) or more.

Check if the same DTC is recorded .

  • Result:
  • ConditionProceed to
    DTCs (C0278/11 and/or C0279/12) are not outputA
    DTCs (C0278/11 and/or C0279/12) are outputB
  • HINT:
If a speed signal of 4 mph (6 km/h) or more is input to the skid control ECU, with the engine switch on (IG) and the stop light switch off, the ECU performs self diagnosis of the motor and solenoid circuits.
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.
If any DTCs are output while jiggling a connector or wire harness of the brake actuator (skid control ECU), inspect and repair the connector or wire harness.
B
REPLACE BRAKE ACTUATOR ASSEMBLY
A
USE SIMULATION METHOD TO CHECK