Faulty knock sensor or damaged sensor wiring specific to cylinder one; Carbon buildup on the piston top or combustion chamber of cylinder one, raising compression and creating hot spots; Low-octane fuel or fuel contaminated with water or incorrect additives; Faulty spark plug or ignition coil on cylinder one causing abnormal combustion; Vacuum leak or intake manifold leak near cylinder one leaning out the mixture; Excessive engine wear such as worn bearings or piston slap on cylinder one; Engine overheating or a faulty cooling fan causing elevated combustion temperatures

DTC codes / P23xx · Ignition system and misfire / P2336

P2336Cylinder #1 Above Knock Threshold

Q: What does code P2336 mean?

Cylinder #1 Above Knock Threshold. P2336 means the engine computer has detected an abnormal knocking or vibration signature specifically on cylinder number one, exceeding the calibrated knock threshold for that cylinder. The powertrain control module uses the knock sensor signal to identify which cylinder is knocking and sets this code when cylinder one's knock intensity stays too high under normal combustion.

P2336 means the engine computer has detected an abnormal knocking or vibration signature specifically on cylinder number one, exceeding the calibrated knock threshold for that cylinder. The powertrain control module uses the knock sensor signal to identify which cylinder is knocking and sets this code when cylinder one's knock intensity stays too high under normal combustion.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Audible pinging or rattling from the engine under acceleration or load
Reduced engine power or sluggish acceleration as the computer retards ignition timing
Rough idle or misfire-like shudder felt through the steering wheel or seat
Poor fuel economy due to prolonged timing retard
In some cases, the engine may enter limp mode to protect itself from damage

Common causes, most likely first

Faulty knock sensor or damaged sensor wiring specific to cylinder one
Carbon buildup on the piston top or combustion chamber of cylinder one, raising compression and creating hot spots
Low-octane fuel or fuel contaminated with water or incorrect additives
Faulty spark plug or ignition coil on cylinder one causing abnormal combustion
Vacuum leak or intake manifold leak near cylinder one leaning out the mixture
Excessive engine wear such as worn bearings or piston slap on cylinder one
Engine overheating or a faulty cooling fan causing elevated combustion temperatures

How to diagnose and fix it

Verify fuel octane rating and condition; drain and refill with the correct grade if contamination is suspected
Inspect and test the knock sensor and its wiring for cylinder one, checking resistance and signal output with a scan tool
Replace spark plugs and inspect the ignition coil on cylinder one for signs of wear or misfire
Perform a cylinder compression test and leak-down test on cylinder one to rule out mechanical faults
Use a borescope to inspect the combustion chamber of cylinder one for carbon deposits and clean if necessary
Check for vacuum leaks around the intake manifold and cylinder one intake runner using a smoke machine
Reflash or update the powertrain control module software if a known calibration issue exists for this code

What most technicians miss on P2336

A knock sensor code for a single cylinder often points to a mechanical issue like carbon buildup or a failing injector rather than a faulty sensor, so replacing the sensor first is a common misdiagnosis.
The knock sensor may be functioning correctly and reporting real knock caused by a lean fuel mixture from a dirty fuel injector on cylinder one, which is frequently overlooked.
P2336 can be set by engine noise that mimics knock, such as a loose heat shield or a failing accessory drive belt tensioner, so always listen to the engine mechanically before condemning the sensor.
On some vehicles, a faulty engine coolant temperature sensor can cause the computer to run the engine too hot, leading to knock on cylinder one without any other obvious symptoms.
After repairing the root cause, the code may persist until the knock learn or adaptive strategy is reset with a scan tool, so clearing codes alone may not be enough.

Can I keep driving with P2336?

You can drive the vehicle short distances at moderate speed to a repair shop, but avoid heavy acceleration, towing, or high-load driving because continued knock can damage pistons and bearings. If the check engine light is flashing or the engine is making loud knocking noises, stop driving and have it towed.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.