P050B
- Powertrain
- Generic (SAE)
- Emissions
Diagnose soon
Usually safe to drive short distances, but the fault will not clear itself and can worsen or fail an emissions test.
Cold Start Ignition Timing Performance
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.
During cold-start the ECU retards ignition timing to raise exhaust temperature for catalyst light-off. The strategy does not deliver the expected timing - feedback from knock sensor or combustion model shows ignition too far advanced or retarded for the demanded calibration.
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
| # | Cause | How often | Component |
|---|---|---|---|
| 1 | Knock sensor drift causes wrong feedback | Very common | — |
| 2 | Cam phaser offset against crank | Common | — |
Ordering reflects how often each cause is responsible in general, not a probability for your vehicle. Confirm by testing.
- Ignition Timing Strategy
- Knock Sensor
- Cam Position 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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