P2337: Cylinder 2 Above Knock Threshold

What it means

The knock sensor channel for cylinder 2 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 listens to knock-sensor signals and adjusts ignition timing to protect the engine. P2337 means the signal assigned to cylinder 2 exceeded the permitted knock threshold despite that response, which can reflect true detonation or a faulty sensor signal.

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. Save freeze-frame data and check knock retard, engine load, and temperature around the cylinder 2 threshold event.
2. Verify that the fuel meets the vehicle's required octane rating, especially if the symptom started after a fill-up.
3. Check for actual pinging under the conditions recorded and look for signs of overheating or other engine problems.
4. Inspect the cylinder 2 knock-sensor connector and wiring for corrosion, looseness, or physical damage.
5. If the signal remains abnormal, test the cylinder 2 sensor circuit and investigate combustion deposits or faults according to the manufacturer's procedure.

Common fixes

• Refuel with gasoline meeting the manufacturer's required octane rating.
• Repair damaged or loose cylinder 2 knock-sensor wiring and connector terminals.
• Correct a confirmed cooling or engine-operation problem causing detonation.
• Replace the knock sensor if testing identifies a sensor or circuit fault.
• Resolve confirmed cylinder 2 deposits or combustion issues using the manufacturer's procedure.

Can I keep driving?

Drive gently and avoid heavy load or towing while pinging is present, since continued detonation can harm the engine. Stop if the rattling is severe or occurs during light acceleration.