What Does P2336 Mean?
Cylinder 1 Above Knock Threshold indicates the knock sensor system has detected persistent detonation (knock/ping) on cylinder 1 that exceeds the ECM's maximum allowable threshold even after applying maximum ignition timing retard. This means the engine is experiencing abnormal combustion events on cylinder 1 despite the ECM's attempts to correct it.
Common Causes
30%
Carbon deposits on cylinder 1 piston crown or combustion chamber increasing compression ratio
25%
Lean fuel condition on cylinder 1 due to a clogged or failing fuel injector
25%
Faulty knock sensor or knock sensor wiring producing false knock signal
20%
Low-octane fuel or fuel quality issue causing pre-ignition
Diagnostic Steps
1
Step 1: Verify fuel octane rating meets manufacturer specification. Check fuel trim data for cylinder 1 or bank 1 for lean conditions (long-term fuel trim above +10%).
2
Step 2: Monitor knock retard values per cylinder using enhanced scan data. Compare cylinder 1 retard to other cylinders. If only cylinder 1 is elevated, the issue is localized.
3
Step 3: Perform a relative compression test via starter current analysis or Mode $06 to check for abnormal compression on cylinder 1 (carbon buildup raises effective compression).
4
Step 4: Inspect knock sensor mounting torque (typically 15-20 ft-lbs) and wiring for damage, corrosion, or improper routing near ignition wires.
5
Step 5: If carbon buildup is suspected, perform an intake valve cleaning or top engine decarbonization procedure using manufacturer-approved chemicals.
Estimated Repair Cost
$100 - $600
Parts + labor, varies by vehicle and location
Cylinder 1 Above Knock Threshold indicates the knock sensor system has detected persistent detonation (knock/ping) on cylinder 1 that exceeds the ECM's maximum allowable threshold even after applying maximum ignition timing retard. This means the engine is experiencing abnormal combustion events on ...
The most common cause of P2336 (Cylinder 1 Above Knock Threshold) is: Carbon deposits on cylinder 1 piston crown or combustion chamber increasing compression ratio
Typical repair costs for P2336 range from $100 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Persistent knock can cause severe engine damage including piston and bearing failure. Reduce engine load, avoid hard acceleration, and repair promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2336 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition/Combustion System
Difficulty
Type
Generic (SAE)
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