P2336: Cylinder 1 Above Knock Threshold

What it means

The knock sensor channel for cylinder 1 has registered combustion noise above the calibrated knock threshold beyond what the spark retard map can correct. Often associated with low-octane fuel, EGR malfunction or carbon-induced hot spots.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The engine controller uses knock-sensor signals to detect abnormal combustion and adjust ignition timing. P2336 identifies knock above the allowed threshold on the cylinder 1 channel despite the controller's timing response; real detonation or a false knock signal can trigger it.

Common causes

Most likely first.

1. Abnormal combustion knock
2. Knock sensor or wiring fault

Symptoms

• Check-engine light
• Pinging or rattling under acceleration
• Reduced power or sluggish acceleration

How to diagnose it

1. Record freeze-frame data and review knock retard and engine load when the cylinder 1 threshold was exceeded.
2. Check that the fuel in the tank meets the vehicle's required octane rating and note whether the noise began after refueling.
3. Listen for pinging under the reported conditions and inspect for obvious causes of overheating, restricted cooling, or incorrect engine operation.
4. Inspect the cylinder 1 knock-sensor wiring and connector for damage, corrosion, loose fit, or contact with other components.
5. If the knock signal persists, test the sensor circuit and assess cylinder 1 for deposits or other combustion problems using the manufacturer's diagnostic procedure.

Common fixes

• Use fuel meeting the manufacturer's required octane rating.
• Repair damaged or loose cylinder 1 knock-sensor wiring or connector terminals.
• Correct any confirmed engine overheating or combustion-system fault.
• Replace the knock sensor only if circuit and sensor testing confirms it is faulty.
• Address confirmed carbon deposits or other cylinder 1 combustion causes using the manufacturer's procedure.

Can I keep driving?

Avoid heavy acceleration, towing, and high engine load while pinging continues, because sustained detonation can damage the engine. If the noise is loud or persists at light load, stop driving and have the cause checked.