Engine · important priority
Knock Sensor Replacement Cost & Pricing
Replace the knock sensor that detects engine detonation (knocking) and signals the ECM to retard ignition timing to protect the engine. A faulty sensor triggers a check engine light (P0325–P0332), causes the ECM to over-retard timing, and reduces power and fuel economy.
Typical Knock Sensor Replacement cost
$120–$450, with an average estimate of $250 before vehicle-specific adjustments.
What to expect
Difficulty: moderate. Typical labor time: 1–4 hours.
Mechanic's tip
Access is the big variable — some knock sensors are easy to reach, while others are buried under the intake manifold (common on GM V6 engines). On those buried sensors, intake removal alone can take 2–3 hours. The wiring harness to the sensor often corrodes or breaks; inspect and replace the pigtail connector if damaged. Using regular fuel in an engine requiring premium is a common cause of knock sensor-related codes from actual detonation.