Park Brake Switch Circuit Failure
Indicates a malfunction in the park brake switch circuit.
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)
The park brake switch isn't working like it should. This means the system can't tell if the parking brake is applied or not, which can lead to safety issues like rolling away if the truck is parked on a slope.
What the computer is actually seeing
The ECM monitors the voltage from the park brake switch. It expects a specific low voltage (around 0.5V when the brake is released) and a high voltage (around 12V when applied). If it sees abnormal values, it triggers this code.
What a healthy reading looks like
Park brake applied: Voltage close to 12V; Park brake released: Voltage close to 0.5V.
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 park brake switch and the ECM. Look for fraying or corrosion. Decision Point: Are there any visible issues? If yes, repair as needed. If no, proceed to step 2.
- 22. Check the park brake switch operation. Disconnect the switch connector and use a multimeter to check continuity. Decision Point: Does the switch show continuity when the park brake is engaged? If yes, the switch is good. If no, replace the switch.
- 33. With the ignition on, measure the voltage at the connector with the park brake applied and released. Decision Point: Are the readings around 12V when applied and 0.5V when released? If yes, proceed to step 4. If no, repair the wiring as needed.
- 44. Look for a bad ground connection to the ECM. Test the ground for continuity. Decision Point: Is the ground good? If yes, the issue may be with the ECM. If no, repair the ground connection.
Common causes
- Faulty park brake switch
- Damaged wiring or connectors
- Poor ground connection
- Dirty or corroded connectors
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to fix this soon as it can affect your parking brake operation, which is crucial for safety.
Will this code come back after resetting it?
If there's a persistent issue, the code will likely return after a short period.
Why does this code appear with other SPN codes?
Multi-fault codes can indicate similar system failures, often related to the park brake or its electrical system.
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