A Knock Sensor (KS) is designed to detect vibrations caused by engine knock or detonation — the uncontrolled combustion of air-fuel mixture in the cylinders. The sensor sends a voltage signal to the vehicle’s onboard computer (either the Powertrain Control Module [PCM] or Engine Control Unit [ECU]), which then adjusts ignition timing to eliminate knock and protect the engine.
Knock Sensors are typically mounted on the engine block, cylinder head, or intake manifold. They act as sensitive microphones that help the ECU precisely detect pinging or detonation and adjust engine timing for smoother performance, improved efficiency, and reduced emissions.
How It Works:
- The Knock Sensor contains a piezoelectric crystal that generates a small voltage when it detects vibration.
- The ECU monitors this signal and compares it against preset data tables to determine if knocking is occurring.
- When knock is detected, the ECU retards ignition timing to prevent detonation and safeguard engine components.
- This process helps maintain optimal performance and fuel economy under all driving conditions.
Product Features & Benefits from Walker Products:
- Exact OE Fit: Direct replacement design for easy installation and precise signal detection.
- OE Replacement Quality: Meets or exceeds original equipment specifications for accuracy and durability.
- Rugged Construction: Built to withstand extreme heat, vibration, and chemical exposure.
- Restores Engine Performance: Enables proper ignition timing and prevents harmful detonation.
- Aftermarket Expertise: Backed by over 75 years of experience in high-quality engine management components.
Symptoms of a Failing Knock Sensor
- Audible engine knocking or pinging sounds.
- Reduced engine power or hesitation during acceleration.
- Poor fuel economy.
- Check Engine Light (CEL) illuminated on the dashboard.
Common Check Engine Light (CEL) / OBD-II Codes
On-Board Diagnostics (OBD) systems have been required in vehicles since the late 1980s, becoming standardized as OBD-II in 1996. These systems monitor emissions and performance-related components, including Knock Sensors.
The following codes are commonly associated with Knock Sensors and should be used as a general guide only. Walker Products will not be held responsible for any use of this information. Always consult a qualified technician and follow manufacturer and EPA guidelines for diagnosis, replacement, and ECU/PCM relearn procedures.
- P0324 – Knock Control System Error
- P0325 – Knock Sensor 1 Circuit
- P0326 – Knock Sensor 1 Circuit Range/Performance
- P0327 – Knock Sensor 1 Circuit Low
- P0328 – Knock Sensor 1 Circuit High
- P0329 – Knock Sensor 1 Circuit Intermittent
- P032A – Knock Sensor 3 Circuit
- P032B – Knock Sensor 3 Circuit Range/Performance
- P032C – Knock Sensor 3 Circuit Low
- P032D – Knock Sensor 3 Circuit High
- P032E – Knock Sensor 3 Circuit Intermittent
- P0330 – Knock Sensor 2 Circuit
- P0331 – Knock Sensor 2 Circuit Range/Performance
- P0332 – Knock Sensor 2 Circuit Low
- P0333 – Knock Sensor 2 Circuit High
- P0334 – Knock Sensor 2 Circuit Intermittent
- P033A – Knock Sensor 4 Circuit
- P033B – Knock Sensor 4 Circuit Range/Performance
- P033C – Knock Sensor 4 Circuit Low
- P033D – Knock Sensor 4 Circuit High
- P033E – Knock Sensor 4 Circuit Intermittent
- P06B6 – Internal Control Module Knock Sensor Processor 1 Performance
- P06B7 – Internal Control Module Knock Sensor Processor 2 Performance
- P2336 – Cylinder 1 Above Knock Threshold
- P2337 – Cylinder 2 Above Knock Threshold
- P2338 – Cylinder 3 Above Knock Threshold
- P2339 – Cylinder 4 Above Knock Threshold
- P2340 – Cylinder 5 Above Knock Threshold
- P2341 – Cylinder 6 Above Knock Threshold
- P2342 – Cylinder 7 Above Knock Threshold
- P2343 – Cylinder 8 Above Knock Threshold
- P2344 – Cylinder 9 Above Knock Threshold
- P2345 – Cylinder 10 Above Knock Threshold
- P2346 – Cylinder 11 Above Knock Threshold
- P2347 – Cylinder 12 Above Knock Threshold