DTC C0278/11: Open in ABS Solenoid Relay Circuit; DTC C0279/12: Short to B+ in ABS Solenoid Relay Circuit: Wiring Diagram

1. Remove the ABS2 fuse from engine room No. 1 R/B.
2. Measure the resistance according to the value(s) in the table below.

Standard resistance 

1. NG: REPLACE ABS2 FUSE 
   Fig 2: Identifying ABS2 Fuse

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. OK: Go To Next Step 

1. Install the ABS2 fuse.
2. Disconnect the skid control ECU connector.
3. Measure the voltage according to the value(s) in the table below.

   Standard voltage 

   TESTER CONNECTION SPECIFIED CONDITION
   
   

   Tester Connection	Condition	Specified Condition
   A14-31 (+BS) - Body ground	Always	10 to 14 V

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

Standard resistance 

1. NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (+BS OR GND CIRCUIT) 
   Fig 3: Identifying Connector Terminals Skid Control ECU

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. OK: Go To Next Step 

1. Reconnect the skid control ECU connector.
2. Clear the DTC (See DTC CHECK / CLEAR  ).
3. Start the engine.
4. Drive the vehicle at the speed of 4 mph (6 km/h) or more.
5. Check if the same DTC is recorded (See DTC CHECK / CLEAR  ).

   Result 

   RESULT REFERENCE CHART
   
   

   Condition	Proceed to
   DTCs (C0278/11 and/or C0279/12) are not output	A
   DTCs (C0278/11 and/or C0279/12) are output	B

   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