P034A — Crankshaft Position Sensor - Crankshaft Start Position Incorrect
At engine start the crankshaft position reported by the sensor does not match the calibrated start window — typically a wrong tone-wheel installation, sensor air gap, or PCM not synchronised after a relearn.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Crankshaft position sensor
- Flywheel
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Tone wheel misindexed or relearn pending
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.