Anti-Lock Brake System

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ANTI-LOCK BRAKE SYSTEM: C0278/11,C0279/12: Open in ABS Solenoid Relay Circuit

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.
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 self diagnosis performed when the vehicle starts running.
The ABS solenoid relay is housed in the skid control ECU in the actuator assembly.






WIRING DIAGRAM





INSPECTION PROCEDURE
HINT: When C1241/41 is output together with C0278/11 and/or C0279/12, inspect and repair the trouble areas indicated by C1241/41 first Low Battery Positive Voltage or Abnormally High Battery Positive Voltage - ABS (Antilock Brake System).

PROCEDURE

1. INSPECT ABS NO. 3 FUSE




(a) Remove the ABS NO. 3 fuse from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPLACE ABS NO. 3 FUSE
OK -- Continue to next step.
2. INSPECT SKID CONTROL ECU (+BS TERMINAL)




(a) Install the ABS NO. 3 fuse.
(b) Disconnect the skid control ECU connector.
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (+BS CIRCUIT)
OK -- Continue to next step.
3. INSPECT SKID CONTROL ECU (GND1 TERMINAL)




(a) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT)
OK -- Continue to next step.
4. 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.
(a) Reconnect the skid control ECU connector.
(b) Clear the DTCs ABS (Antilock Brake System).
(c) Start the engine.
(d) Drive the vehicle at a speed of 20 km/h (12 mph) or more for 30 seconds or more.
(e) Check if the same DTC is recorded ABS (Antilock Brake System).
Result:





HINT:
- 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.
- If the normal system code is output (no trouble codes are 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 assembly (skid control ECU), inspect and repair the connector or wire harness.
- It is suspected that the DTCs were output due to a bad connection of the connector terminal.

B -- REPLACE BRAKE ACTUATOR ASSEMBLY
A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)