DTC C0278: Open in ABS Solenoid Relay Circuit; DTC C0279: Short in ABS Solenoid Relay Circuit [08/2015 - 08/2019]: Procedure

1. Turn the ignition switch off.
2. Disconnect the A53 skid control ECU (brake actuator assembly) connector.
3. Measure the voltage according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   A53-12 (+BS) - Body ground	Always	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *a	Front view of wire harness connector (to Skid Control ECU (Brake Actuator Assembly))

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (+BS CIRCUIT) 

Result: 

OK 

See step  2

1. Disconnect the A53 skid control ECU (brake actuator assembly) connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A53-1 (GND1) - Body ground	Always	Below 1 Ω

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT) 

Result: 

OK 

See step  3

HINT: 

This code is stored when a problem is identified in the skid control ECU (brake actuator assembly).

The solenoid circuit is in the skid control ECU (brake actuator assembly).

Therefore, solenoid circuit inspections and solenoid unit inspections cannot be performed. Be sure to check if the DTC is output before replacing the skid control ECU (brake actuator assembly).

1. Reconnect the skid control ECU (brake actuator assembly) connector.
2. Clear the DTC (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).
3. Start the engine.
4. Drive the vehicle at a speed of 20 km/h (12 mph) or more for 30 seconds or more.
5. Check if the same DTC is recorded (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).
   RESULT
   
   

   Result	Proceed to
   DTC not output	A
   DTC output	B

   HINT: 

   • If a speed signal of 6 km/h (4 mph) or more is input to the skid control ECU (brake actuator assembly) with the ignition switch to 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 (the trouble code is not output), slightly jiggle the connectors, wire harnesses and fuses of the skid control ECU (brake actuator assembly). Make sure that no DTCs are output.
   • If any DTCs are output while jiggling a connector or wire harness of the skid control ECU (brake actuator assembly), inspect and repair the connector or wire harness. The DTCs were probably output due to a bad connection of the connector terminal.

Result: 

A 

USE SIMULATION METHOD TO CHECK 

(Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2015 - 08/2019] )

Result: 

B 

REPLACE BRAKE ACTUATOR ASSEMBLY 

(Refer to REMOVAL [08/2015 - 08/2019] )