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.
Pinpoint Test Cw-2: Brake Pedal Switch Faults: Notes
Refer to VEHICLE DYNAMIC SYSTEMS for schematic and connector information.
Normal Operation and Fault Conditions
The ABS module receives BPP switch input from the PCM through the GWM over the HS-CAN. The ABS module compares this information against brake fluid pressure input to determine if the 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.
REFER to: Anti-Lock Brake System (ABS) and Stability Control - System Operation and Component Description .
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Condition |
|---|---|---|
| ABS C0040:64 | Brake Pedal Switch "A": Signal Plausibility Failure | There are 2 conditions which can cause this DTC to set in the ABS module. The first condition is if the brake hydraulic pressure is more than 1, 000 KPA (10 bar) on light duty vehicles or 3, 000 kpa (30 bar) on heavy duty vehicles, the driver is NOT pressing the brake pedal, there are no active hydraulic control functions. The second condition is if the brake hydraulic fluid pressure is greater than 8, 000 kpa (80 bar), the driver is NOT pressing the brake pedal and there are no hydraulic system Diagnostic Trouble Codes present. |
| ABS C0040:01 | Brake Pedal Switch "A": General Electrical Failure | When the ABS module detects the brakelamp output signal is shorted to ground, this DTC is set. |
Possible Sources
- Wiring, terminals or connectors
- Brake pedal (stoplamp) switch
- Network communication concern
- ABS and HCU assembly
- Pressing both pedals (brake and accelerator) at the same time
NO RELATED
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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.