Brake Pedal Position Sensor Circuit Low Voltage
The brake pedal position sensor is reading too low a voltage.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
Inside the truck's computer, there's a sensor linked to the brake pedal that tells how far down the pedal is pressed. If it’s below about 0.5 volts when it should be around 0.5 to 4.5 volts, that means it's not working right.
What the computer is actually seeing
The ECM expects a voltage signal from the brake pedal position sensor between 0.5V and 4.5V. If the signal drops below 0.5V, it triggers this fault code.
What a healthy reading looks like
Brake pedal position sensor should output 0.5V to 4.5V based on pedal position.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the wiring and connectors between the brake pedal position sensor and the ECM. Look for fraying, corrosion, or loose connections. Decision Point: Are the wiring and connectors in good condition? If yes, proceed to step 2. If no, repair or replace as necessary.
Common causes
- Faulty brake pedal position sensor
- Damaged wiring or connectors
- Low supply voltage to the sensor
- Corroded connectors
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code present?
It's not ideal. The brakes may not function as intended, so fix it as soon as possible.
Will this code come back after I clear it?
If the underlying issue isn't fixed, the code will likely return.
Why does this code pair with SPN 3934?
SPN 3934 relates to high voltage in the same system, indicating there could be an issue with the sensor or its circuit.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →