Diagnostic code C0278 C0279 ABS Solenoid Relay Circuit. Lexus IS250 IS220D

Description

Wiring diagram

Inspection procedure

INSPECT ABS3 FUSE

INSPECT ABS SOLENOID RELAY

INSPECT ENGINE ROOM NO. 3 RELAY BLOCK (POWER SOURCE TERMINAL)

CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM NO. 3 RELAY BLOCK)

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.

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 Condition Trouble Area
C0278/11 When any of the following (1 or 2) is detected:
  1. All of the following conditions continue for 0.2 seconds or more.
    1. The IG1 terminal voltage is between 9.5 and 17.2 V.
    2. The solenoid relay contact is open when the relay is ON.
  2. All of the following conditions continue for 0.2 seconds or more.
    1. IG1 terminal voltage becomes lower than 9.5 V or less when the relay is turned on.
    2. The relay contact remains open.
  1. ABS3 fuse
  2. ABS solenoid relay
  3. ABS solenoid relay circuit
  4. Skid control ECU
C0279/12 Immediately after the engine switch is turned on (IG), the solenoid relay contact is closed for 0.2 seconds when the relay is turned off.
  1. ABS3 fuse
  2. ABS solenoid relay
  3. ABS solenoid relay circuit
  4. Skid control ECU

Wiring diagram

Wiring diagram. Diagnostic code C0278 C0279 ABS Solenoid Relay Circuit. Lexus IS250 IS220D

Inspection procedure

NOTICE:

When replacing the skid control ECU, perform zero point calibration and store system information .

 

1.INSPECT ABS3 FUSE

Remove the ABS3 fuse from the engine room. Diagnostic code C0278 C0279 ABS Solenoid Relay Circuit. Lexus IS250 IS220D

  1. Remove the ABS3 fuse from the engine room No. 1 R/B.

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

Standard resistance:

Tester Connection Condition Specified Condition
ABS3 (25 A) fuse Always Below 1 ?
  NG  
REPLACE ABS3 FUSE
 
OK  
   

2.INSPECT ABS SOLENOID RELAY

Install the ABS3 fuse. Diagnostic code C0278 C0279 ABS Solenoid Relay Circuit. Lexus IS250 IS220D

  1. Install the ABS3 fuse.

  1. Remove the ABS SOL relay.

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

Standard resistance:

Tester Connection Condition Specified Condition
3 - 5 Always 10 k? or higher
3 - 5 Apply B+ between terminals 1 and 2 Below 1 ?
  NG  
REPLACE ABS SOLENOID RELAY
 
OK  
   

3.INSPECT ENGINE ROOM NO. 3 RELAY BLOCK (POWER SOURCE TERMINAL)

Measure the voltage according to the value(s) in the table below. Diagnostic code C0278 C0279 ABS Solenoid Relay Circuit. Lexus IS250 IS220D

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

Standard voltage:

Tester Connection Condition Specified Condition
ABS SOL relay terminal 3 - Body ground Always 10 to 14 V
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
 
OK  
   

4.CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM NO. 3 RELAY BLOCK)

Disconnect the skid control ECU connectors. Diagnostic code C0278 C0279 ABS Solenoid Relay Circuit. Lexus IS250 IS220D

  1. Disconnect the skid control ECU connectors.

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

Standard resistance:

LHD:

Tester Connection Condition Specified Condition
A35-11 (R+) - ABS SOL relay terminal 1 Always Below 1 ?
A35-11 (R+) - Body ground Always 10 k? or higher
J78-2 (SR) - ABS SOL relay terminal 2 Always Below 1 ?
J78-2 (SR) - Body ground Always 10 k? or higher
J78-13 (AST) - ABS SOL relay terminal 5 Always Below 1 ?
J78-13 (AST) - Body ground Always 10 k? or higher

RHD:

Tester Connection Condition Specified Condition
J98-11 (R+) - ABS SOL relay terminal 1 Always Below 1 ?
J98-11 (R+) - Body ground Always 10 k? or higher
J78-2 (SR) - ABS SOL relay terminal 2 Always Below 1 ?
J78-2 (SR) - Body ground Always 10 k? or higher
J78-13 (AST) - ABS SOL relay terminal 5 Always Below 1 ?
J78-13 (AST) - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

5.RECONFIRM DTC

  1. Install the ABS SOL relay.

  1. Reconnect the skid control ECU connectors.

  1. Clear the DTC .

  1. Start the engine.

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

  1. Check if the same DTC is recorded .

Result:

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:

  1. 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.
  2. 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 and brake actuator assembly. Make sure that no DTCs are output.
  3. If any DTCs are output while jiggling a connector or wire harness of the skid control ECU and brake actuator assembly, inspect and repair the connector or wire harness.
  B  
REPLACE SKID CONTROL ECU
 
A  
   
USE SIMULATION METHOD TO CHECK