P032B: Knock/Combustion Vibration Sensor C Circuit Range/Performance

What it means

Knock sensor C signal is in electrical range but plausibility check fails — typically a loose mounting, wrong torque, or sensor element drift.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

Knock sensor C monitors combustion vibration on engines equipped with multiple sensors, and the control module uses its signal to manage ignition timing. P032B sets when the signal is present but fails the module's plausibility check, which can result from loose mounting, incorrect torque, sensor drift, or a signal-path problem.

Common causes

Most likely first.

1. Sensor loose
2. Gateway module routing CAN messages incorrectly
3. 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

1. Review freeze-frame and live data for sensor C and note the engine load and speed when its signal failed the plausibility check.
2. Locate knock sensor C using vehicle service information and inspect its connector, wiring, and mounting for looseness, corrosion, or damage.
3. Check for abnormal mechanical vibration near the area monitored by sensor C that could distort its reading.
4. Verify sensor C is mounted and tightened to the manufacturer's specification.
5. If the mounting and wiring are sound, test the sensor C signal and circuit according to the manufacturer's procedure.

Common fixes

• Mount sensor C correctly and tighten it to the manufacturer's specification.
• Repair a loose connector or damaged wiring in the sensor C circuit.
• Correct an identified source of abnormal vibration.
• Replace knock sensor C if its signal fails testing.

Can I keep driving?

Avoid high engine loads until diagnosed because the module may reduce power and may not interpret knock on sensor C's monitored area reliably. Stop if persistent pinging is audible.