P2337 — Cylinder 2 Above Knock Threshold
powertrain (engine/transmission)
Is it safe to drive?
Drive with caution Drive gently and avoid hard acceleration. With knock detection off, the engine is not protected from detonation — sustained pinging under load can damage pistons and bearings over time.
How to diagnose with an OBD scanner
- Read the code and freeze frame Connect an OBD2 scanner, confirm P2337 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
- Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
- Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the knock (detonation) detection for damage, corrosion, chafing or poor contact.
- Subsystem check Inspect the knock sensor connector and wiring — heat and vibration damage them often.
- Subsystem check Check sensor torque and mounting surface; an improperly seated sensor reads incorrectly.
- Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2337 does not return.
Approximate repair cost
Repair cost depends on which component actually failed. Typical scenarios for P2337 (parts and labor, USD, independent shop rates): Decarbonization service: $150–$400; Repair sensor wiring: $80–$250; Replace the knock sensor: $150–$450. Overall, fixing P2337 usually costs between $80 and $450. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.
Common questions
How do I diagnose P2337 myself?
Start with a scan: confirm P2337, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the knock (detonation) detection, and verify the suspect component against live data before buying parts.
What does OBD2 code P2337 mean?
Cylinder 2 Above Knock Threshold (P2337): a powertrain (engine/transmission) fault affecting the knock (detonation) detection. Short, gentle driving to a shop is usually possible. Most often caused by low-octane or contaminated fuel, failed knock sensor, damaged knock sensor wiring or connector.
How much does it cost to fix P2337?
Decarbonization service — $150–$400; Repair sensor wiring — $80–$250; Replace the knock sensor — $150–$450. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.
Is it safe to drive with P2337?
Drive gently and avoid hard acceleration. With knock detection off, the engine is not protected from detonation — sustained pinging under load can damage pistons and bearings over time.
What are the symptoms of P2337?
Drivers most often notice: often no audible symptoms, Check Engine Light on, metallic pinging under acceleration, reduced power (ECM retards timing).
What does P2337 mean?
P2337 (Cylinder 2 Above Knock Threshold) is stored when self-diagnostics detect abnormal readings or behaviour of the knock (detonation) detection. It belongs to the powertrain (engine/transmission) category.
P2337 refers specifically to cylinder 2. On inline engines cylinders are counted from the front (belt end); on V-engines the numbering depends on the manufacturer, so check the firing-order diagram for your exact model. Location matters for the repair bill: some cylinders require intake manifold removal, which adds labor time.
To set P2337, the control module compares live readings of the knock (detonation) detection against calibrated limits, usually over several drive cycles. Alongside the code it stores a freeze frame — a snapshot of rpm, load, coolant temperature and vehicle speed at the moment of failure. Reading that snapshot first saves diagnostic time.
Common symptoms of P2337
- often no audible symptoms
- Check Engine Light on
- metallic pinging under acceleration
- reduced power (ECM retards timing)
- worse fuel economy
What causes P2337?
- low-octane or contaminated fuel
- failed knock sensor
- loose sensor mounting or incorrect torque
- engine carbon buildup causing real detonation
- damaged knock sensor wiring or connector
How to diagnose P2337
- Connect an OBD2 scanner, confirm P2337 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
- Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
- Visually inspect the wiring harness and connectors related to the knock (detonation) detection for damage, corrosion, chafing or poor contact.
- Inspect the knock sensor connector and wiring — heat and vibration damage them often.
- Check sensor torque and mounting surface; an improperly seated sensor reads incorrectly.
- Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2337 does not return.
How to fix P2337
Start with the cheapest and most common causes before replacing expensive parts:
- Decarbonization service — $150–$400
- Repair sensor wiring — $80–$250
- Replace the knock sensor — $150–$450
How much does it cost to fix P2337?
Repair cost depends on which component actually failed. Typical scenarios for P2337 (parts and labor, USD, independent shop rates):
- Decarbonization service: $150–$400
- Repair sensor wiring: $80–$250
- Replace the knock sensor: $150–$450
Overall, fixing P2337 usually costs between $80 and $450. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.
Can you drive with P2337?
Drive gently and avoid hard acceleration. With knock detection off, the engine is not protected from detonation — sustained pinging under load can damage pistons and bearings over time.