P2338
- Powertrain
- Manufacturer-specific
- Emissions
Diagnose soon
Usually safe to drive short distances, but the fault will not clear itself and can worsen or fail an emissions test.
Cylinder 3 Above Knock Threshold
This code is in our catalogue but has not yet been through editorial review, so the guidance below is limited to what our structured data supports. We publish deeper diagnostic content only after a code has been reviewed — here is why.
The knock sensor channel for cylinder 3 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.
A trouble code records what a control module measured. It does not identify which part failed. Test before replacing anything.
- Safe to drive
- Usually safe to drive short distances, but the fault will not clear itself and can worsen or fail an emissions test.
- Urgency
- Diagnose soon
- Will it pass emissions
- No
- Check engine light
- Solid
- Clearing the light
- A completed drive cycle is normally required before the monitor re-runs and the light can clear.
| # | Cause | How often | Component |
|---|---|---|---|
| 1 | Low octane fuel used | Very common | — |
| 2 | Carbon deposits causing pre-ignition | Common | — |
Ordering reflects how often each cause is responsible in general, not a probability for your vehicle. Confirm by testing.
- Spark Plug
- Knock Sensor
- Definition
- Generic code set (SAE J2012 / ISO 15031-6) via the OBDexopen database, dedicated to the public domain under CC0-1.0.
- Diagnostic guidance
- Written and reviewed in-house. See our editorial policy.
- Review status
- Awaiting review
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