Pinpoint Test F: DTC C1266

Anti-Lock Control

Pinpoint Tests

Pinpoint Test F: DTC C1266

Refer to Wiring Diagram Set 42, Vehicle Dynamic Systems for schematic and connector information. Diagrams By Number

Normal Operation

The operating voltage required for ABS module isolation valve operation is between 10 and 17 volts.

Fused battery voltage is supplied to the ABS module for the valves by the Battery Junction Box (BJB).

- DTC C1266 (ABS Valve Power Relay Circuit Failure) - this DTC sets in the ignition cycle if the ABS module detects an open or a short to ground on the valve power feed circuit. DTCs set in the ignition cycle can only be cleared by cycling the ignition off and on once the fault has been corrected.

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- ABS module

PINPOINT TEST F: DTC C1266

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

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F1 CHECK FOR VOLTAGE TO THE ABS MODULE

- Ignition OFF.
- Disconnect: ABS Module C135.
- Measure the voltage between ABS module C135-25, circuit SBB36 (GN/RD), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to F2.

No
VERIFY that Battery Junction Box (BJB) fuse 36 (30A) is OK. If OK, REPAIR circuit SBB36 (GN/RD). If not OK, REFER to the Wiring Diagrams to identify possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test. Diagrams By Number

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F2 CHECK THE ABS MODULE GROUND CIRCUIT FOR AN OPEN

- Ignition OFF.
- Measure the resistance between ABS module C135-38, circuit GD121 (BK/YE), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
GO to F3.

No
REPAIR circuit GD121 (BK/YE). CLEAR the DTCs. REPEAT the self-test.

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F3 CHECK FOR CORRECT ABS MODULE OPERATION

- Disconnect: ABS Module C135.
- Check ABS module connector for:
- corrosion
- damaged pins
- pushed-out pins
- Connect: ABS Module C135.
- Is the concern still present?

Yes
INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module Service and Repair. CLEAR the DTCs. REPEAT the self-test.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.

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