Lexus IS250 IS220d GSE20 ALE20 - BRAKE CONTROL
INSPECT ENGINE ROOM NO. 3 RELAY BLOCK (POWER SOURCE TERMINAL)
CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE ROOM NO. 3 RELAY BLOCK)
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: 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. | ABS3 fuse ABS solenoid relay ABS solenoid relay circuit 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. | ABS3 fuse ABS solenoid relay ABS solenoid relay circuit Skid control ECU |
WIRING DIAGRAM
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 No. 1 R/B.
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 Ω
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OK | |
2.INSPECT ABS SOLENOID RELAY |

Install the ABS3 fuse.
Remove the ABS SOL relay.
Measure the resistance according to the value(s) in the table below.
- Standard resistance:
Tester Connection Condition Specified Condition 3 - 5 Always 10 kΩ or higher 3 - 5 Apply B+ between terminals 1 and 2 Below 1 Ω
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OK | |
3.INSPECT ENGINE ROOM NO. 3 RELAY BLOCK (POWER SOURCE TERMINAL) |

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

Disconnect the skid control ECU connectors.
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 Ω A35-11 (R+) - Body ground Always 10 kΩ or higher J78-2 (SR) - ABS SOL relay terminal 2 Always Below 1 Ω J78-2 (SR) - Body ground Always 10 kΩ or higher J78-13 (AST) - ABS SOL relay terminal 5 Always Below 1 Ω J78-13 (AST) - Body ground Always 10 kΩ or higher - RHD:
Tester Connection Condition Specified Condition J98-11 (R+) - ABS SOL relay terminal 1 Always Below 1 Ω J98-11 (R+) - Body ground Always 10 kΩ or higher J78-2 (SR) - ABS SOL relay terminal 2 Always Below 1 Ω J78-2 (SR) - Body ground Always 10 kΩ or higher J78-13 (AST) - ABS SOL relay terminal 5 Always Below 1 Ω J78-13 (AST) - Body ground Always 10 kΩ or higher
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OK | |
5.RECONFIRM DTC |
Install the ABS SOL relay.
Reconnect the skid control ECU connectors.
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:
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:
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A | ||
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