What it means
Clutch pedal switch A input reads stuck low — short to ground or stuck-closed contact. The ECM may treat clutch as constantly disengaged, blocking cruise control or affecting cranking permission on manual transmissions.
At a glance
- Usually lights the check-engine light
How it works
Clutch pedal switch A signals the clutch state to the engine control module for functions such as starting permission and cruise control. P0831 means the switch A input is being read low when the module expects a higher state, which can result from a grounded wire or a contact stuck closed.
Common causes
Most likely first.
- Switch wire shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Record freeze-frame data and monitor clutch switch A live data while pressing and releasing the pedal to confirm whether the input stays low.
- Inspect switch A's connector and harness from the clutch pedal for corrosion, pushed-back pins, or insulation worn through and touching ground.
- With the wiring diagram, test the switch A signal wire for a short to ground using the manufacturer's procedure.
- Check switch A operation and connector contact condition against the manufacturer's specification to distinguish a stuck contact from a wiring fault.
- If the switch and harness pass, test the module input circuit as specified by the manufacturer.
Common fixes
- Repair the switch A signal wire where it is shorted to ground.
- Clean or repair corroded or loose terminals in the clutch switch A connector.
- Replace clutch pedal switch A if its contact remains closed when the pedal state should change.
- Repair the module input circuit if testing confirms it is holding the signal low.
Can I keep driving?
Starting permission or cruise control may be affected because the module can interpret switch A as continuously active. Confirm the vehicle starts reliably and avoid cruise control until repaired; if it will not start consistently, do not rely on it for a trip.
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.