Code
P2337
Generic
P — Powertrain
Cylinder 2 Above Knock/Combustion Vibration Sensor Threshold
Views:
UK: 19
EN: 35
RU: 30
AI status
Completed
Completed
100%
Causes
- Faulty or degraded knock/combustion vibration sensor (cylinder 2)
- Damaged, corroded or loose sensor connector or wiring (open, short to ground or to power)
- Improper sensor mounting or loose/incorrect torque at sensor boss
- Engine mechanical problems causing detonation or abnormal vibration (pre-ignition, low compression, carbon hotspots)
- Ignition or fueling problems on cylinder 2 (advanced timing, lean mixture, misfire)
- Low-octane fuel or fuel contamination causing detonation
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Engine pinging, knocking or metallic rapping noise under load
- Reduced engine performance or hesitation under acceleration
- Poor fuel economy
- Rough idle or intermittent misfire (if knock progressed to ignition issues)
- Possible limp-home mode or reduced power depending on vehicle strategy
What to check
- Read and record freeze frame and all stored codes; confirm P2337 is current and note engine conditions when set
- Inspect cylinder 2 knock sensor connector and wiring for corrosion, damage, pin push-out or oil intrusion
- Visually confirm sensor is correctly seated and tightened to manufacturer's torque spec
- Check for related codes (ignition, fuel trim, compression) that could indicate root cause
- Perform a visual/hand inspection for loose components or obvious sources of mechanical noise near sensor mounting
- Use scan tool to monitor knock sensor raw data/live values and compare with other cylinders during a loaded run
Signal parameters
- Typical knock sensor output: low/near 0 mV with no knock, producing AC voltage pulses that increase with vibration amplitude (tens to hundreds of mV)
- Pulse frequency content typically in the kHz range (vehicle-dependent); ECM looks for characteristic amplitude/frequency patterns
- Piezo sensors usually show no meaningful DC continuity — multimeter resistance is not a reliable functional test; use an oscilloscope or dedicated knock-detection tool for waveform analysis
- ECM threshold values vary by manufacturer; a sensor 'above threshold' means the measured vibration signature exceeded the programmed limit for cylinder 2
Diagnostic algorithm
- Confirm code and freeze-frame data. If code is historic, clear and re-run to verify repeatability.
- Visually inspect sensor, connector and wiring for damage, corrosion, oil saturation or pin misalignment. Repair any wiring faults and re-test.
- Verify sensor mounting: remove and inspect mounting hole and sensor boss for damage; reinstall sensor to correct torque. Replace sensor if mounting is loose or damaged.
- Use a scan tool to view knock sensor data or a lab scope to capture the sensor waveform while performing a controlled, safe loaded run or dyno test. Compare amplitude/frequency against other cylinders.
- If no electrical fault is found but real knock is present, check ignition timing, fuel quality (use correct octane), injector operation and fuel trims. Address any fueling or timing issues and re-check for knock.
- Perform compression/leak-down test on cylinder 2 if mechanical causes are suspected (hot spots, low compression, valve issues).
- If wiring and engine condition are good and abnormal waveform persists on cylinder 2 only, replace the knock sensor and re-test.
- After repair, clear codes and perform a road/dyno test under the conditions that previously set the code to confirm the fault is resolved.
Likely causes
- Loose or corroded connector at cylinder 2 knock sensor
- Faulty knock sensor (failed piezo element)
- Local mechanical issue or ignition timing causing real knock on cylinder 2
- Broken or shorted wiring between sensor and ECM
Fault status
Status
Knock/combustion vibration sensor for cylinder 2 reporting signal above allowed threshold. MIL illuminated. May indicate sensor/electrical fault or real detonation/abnormal combustion on cylinder 2.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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