What's involved
What this repair actually is.
The knock sensor listens for harmful 'pinging' inside the engine so the computer can adjust timing before damage occurs. When it fails, the computer runs the engine in a cautious reduced-power mode. On many V6 and V8 engines the sensor sits under the intake manifold, which is what drives the labor range.
Symptoms
How you can tell.
- Check engine light with a knock sensor code
- Noticeable loss of power
- Worse fuel economy
- Pinging or rattling under acceleration
- Failed emissions inspection
If you delay
Without a working knock sensor the computer can't protect the engine from detonation, which can damage pistons over time.
Educational estimate. Real pricing depends on your vehicle, the inspection, parts availability, taxes, and shop rates. Use this as a guide while you shop quotes.