Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Normal Operation and Fault Conditions
The ABS module receives BPP switch input from the PCM through the GWM over the HSCAN. The ABS module compares this information against brake fluid pressure input to determine if the BPP switch input is valid. An incorrectly installed BPP switch can cause a signal plausibility concern. An implausible signal can also be created if a driver is resting one foot on the brake pedal while using the other foot to press the accelerator.
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| C0040:64 | Brake Pedal Switch "A": Signal Plausibility Failure | Sets when the ABS module detects the brake pedal switch input is continuously active for more than 6 minutes when driving faster than 20 km/h (12 mph) or after accelerating up to a speed greater than 40 km/h (24 mph) and decelerating down to a speed less than 3 km/h (2 mph) 4 times with no change in brake pedal switch input. |
| C0044:28 | Brake Pressure Sensor "A": Signal Bias Level Out of Range/Zero Adjustment Failure | Sets when the ABS module detects the brake pedal switch input and the brake pressure input (inside the HCU) do not match. This fault could be set by an incorrectly installed brake pedal switch or brake pedal assembly. |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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