Pinpoint Test U: DTCs C0040:72, C0040:73

Anti-Lock Control - Four-Channel

Pinpoint Tests

Pinpoint Test U: DTCs C0040:72, C0040:73

Normal Operation

The ABS module receives brake pedal input from the PCM over the High Speed Controller Area Network (HS-CAN). The ABS module compares this information against other inputs (wheel speed signals, vehicle speed signal, brake pressure transducer) to determine if the brake pedal input is valid.

- DTC C0040:72 (Brake Pedal Switch "A": Actuator Stuck Open) - sets in continuous memory, if during normal operation, the ABS module cannot detect the brake pedal input or if the brake pedal input does not match information from other sensors (wheel speed signals, vehicle speed signal, brake pressure transducer).
- DTC C0040:73 (Brake Pedal Switch "A": Actuator Stuck Closed) - sets in continuous memory when the ABS module senses vehicle speed and acceleration while the brake pedal input is indicating that the vehicle brakes are applied.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals, or connectors
- Stoplamp switch

PINPOINT TEST U: DTCs C0040:72, C0040:73

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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U1 VERIFY CORRECT STOPLAMP SWITCH INSTALLATION

- Check the stoplamp switch for correct installation.
- Is the stoplamp switch correctly installed?

Yes
GO to U2.

No
REMOVE the stoplamp switch and INSTALL it correctly. REFER to Exterior Lighting Service and Repair. CLEAR the DTCs. TEST DRIVE the vehicle above 40 km/h (25 mph) and CARRY OUT 4 complete stops. REPEAT the self-test.

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U2 CHECK THE STOPLAMPS FOR CORRECT OPERATION

- Check the stoplamps for correct operation by pressing and releasing the brake pedal and observing the stoplamps.
- Do the stoplamps operate correctly?

Yes
GO to U3.

No
REFER to Exterior Lighting Testing and Inspection for further diagnosis of the stoplamps.

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U3 CHECK THE ABS MODULE DTCs

- Review the ABS module DTCs retrieved during Inspection and Verification.
- Is U0100:00 present?

Yes
GO to Pinpoint Test X. Pinpoint Test X: DTC U0100:00

No
GO to U4.

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U4 CHECK THE ABS MODULE BRAKE ON/OFF (BOO_ABS) PID

- Enter the following diagnostic mode on the scan tool: ABS Module DataLogger.
- Monitor the BOO_ABS PID while pressing and releasing the brake pedal.
- Does the PID display match the brake pedal position?

Yes
The system is operating correctly at this time. CLEAR the DTCs. REPEAT the self-test.

No
GO to U5.

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U5 CHECK THE PCM BRAKE ON/OFF (BOO1) PID

- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor the BOO1 PID while pressing and releasing the brake pedal.
- Does the PID display match the brake pedal position?

Yes
The system is operating correctly at this time. CLEAR the DTCs. REPEAT the self-test.

No
REFER to Exterior Lighting Testing and Inspection to diagnose the stoplamp switch.

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