What it means
The park brake apply switch or position sensor reports a circuit fault. The ECU loses the indication whether the parking brake is engaged - relevant for stop-start, hill-hold, and certain shift-interlock strategies.
At a glance
- Usually lights the check-engine light
How it works
The park brake apply switch or position sensor tells the control module whether the parking brake is engaged. The module monitors this circuit for a fault that prevents it from reliably determining the brake’s state, which can affect features such as stop-start or hill-hold.
Common causes
Most likely first.
- Faulty park brake switch or position sensor
- Open or damaged wiring
- Loose or corroded connector
Symptoms
- Park-brake warning light or message may behave incorrectly
- Check-engine or brake warning light may illuminate
How to diagnose it
- Record freeze-frame data and check live park-brake status while applying and releasing the brake to see when the indication fails.
- Inspect the park-brake switch or position sensor and its connector for looseness, corrosion, damage, or poor adjustment.
- Check the wiring between the sensor and control module for breaks, rubbed insulation, or loose connections.
- Use the wiring diagram to test circuit continuity and connections, comparing results with the manufacturer's specification.
- If the wiring and connections are sound, test the switch or sensor output as the brake is applied and released.
Common fixes
- Reconnect and secure a loose park-brake sensor connector.
- Clean or repair corroded connector terminals.
- Repair damaged wiring in the park-brake sensor circuit.
- Adjust or replace a faulty park-brake switch or position sensor.
Can I keep driving?
If the parking brake releases fully and the brake warning remains off, a short, cautious drive may be possible, but the warning or status display may be unreliable. Confirm the brake is released before driving; stop if the brake drags or a brake warning appears.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.