C0040:72

Anti-Lock Control

Pinpoint Test F: DTCs C0040:72 and 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 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 low brake fluid pressure, while the brake pedal input is indicating that the vehicle brakes are applied.

This pinpoint test is intended to diagnose the following:

- Brake pedal position switch

PINPOINT TEST F : DTCs C0040:72 AND C0040:73

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

F1 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 F2.

No
REFER to Lighting and Horns.

F2 CHECK THE ABS MODULE DTCs

- Review the ABS module DTCs retrieved during Inspection and Verification.

Is DTC U0100:00 present?

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

No
For DTC C0040:72 GO to F3.

For DTC C0040:73, INSTALL a new stoplamp switch. CLEAR the DTCs. REPEAT the self-test.

F3 CHECK THE ABS MODULE BRAKE PRESSURE PID

- Enter the following diagnostic mode on the scan tool: ABS Module DataLogger.

- Monitor the BPS_EE12 PID with the brake pedal released.

Does the BPS_EE12 PID show brake pressure lower than 132 psi?

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

No
GO to F4.

F4 CHECK THE ABS MODULE BRAKE PRESSURE PID

- Disconnect: Cruise Control Deactivator Switch C277.

- Remove the cruise control deactivator switch.

- Enter the following diagnostic mode on the scan tool: ABS Module DataLogger.

- Monitor the BPS_EE12 PID with the brake pedal released.

Does the BPS_EE12 PID show brake pressure lower than 132 psi?

Yes
INSTALL a new cruise control deactivator switch. CLEAR the DTCs. REPEAT the self-test.

No
GO to F5.

F5 CHECK THE ABS MODULE BRAKE PRESSURE PID

- Connect: Cruise Control Deactivator Switch C277.

- Enter the following diagnostic mode on the scan tool: ABS Module DataLogger.

- Connect: Stoplamp Switch C278.

- Remove the stoplamp switch.

- Monitor the BPS_EE12 PID with the brake pedal released.

Does the BPS_EE12 PID show brake pressure lower than 132 psi?

Yes
INSTALL a new stoplamp switch. CLEAR the DTCs. REPEAT the self-test.

No
GO to F6.

F6 CHECK FOR CORRECT ABS MODULE OPERATION

- Disconnect: ABS Module.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect: ABS Module.

- Make sure the connector is seated correctly, then operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module . TEST the system for normal operation.

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.