What it means
Knock sensor C signal below lower plausibility — short to ground. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Knock sensor C detects combustion vibration on engines with multiple knock sensors, allowing the control module to adjust ignition timing. P032C sets when sensor C's circuit signal falls below the expected level; a short to ground or a failed sensor can cause the low reading.
Common causes
Most likely first.
- Short to ground
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Check-engine light
- Reduced engine power or acceleration
- Engine knocking may be more noticeable
How to diagnose it
- Check freeze-frame data and live readings for knock sensor C to confirm the low signal and when it occurs.
- Locate sensor C using vehicle service information and inspect its connector and harness for water ingress, corrosion, pushed-back pins, or chafing.
- Trace the sensor C signal wire for contact with ground, especially where the harness passes near the engine or sharp edges.
- Test the sensor C circuit for a short to ground and check continuity to the control module using the circuit diagram and manufacturer's procedure.
- If the wiring and connector pass inspection, test knock sensor C according to the manufacturer's procedure.
Common fixes
- Repair the sensor C signal wire shorted to ground.
- Clean or repair a wet, corroded, or damaged sensor C connector.
- Repair chafed wiring and secure the harness away from ground points.
- Replace knock sensor C if it fails the manufacturer's test.
Can I keep driving?
Keep engine load low and avoid towing because the module may reduce power while knock protection for sensor C's monitored area is compromised. Stop if you hear sustained pinging.
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.