What P0021 means
Posición del árbol de levas A - Exceso de avance o desempeño del sistema (Banco 2)
How to diagnose
- Read freeze frame data. When P0021 set, your ECU snapshotted every sensor at that moment. This tells you what the car was doing when the fault triggered — RPM, load, coolant temp, throttle position, fuel trims. Almost always enough info to figure out the cause without further testing.
- Check for related codes. If you have P0021 plus other codes, fix the earliest one in the chain first — a single root cause often triggers multiple codes.
- Cheap fixes first. For most codes, the order is: inspect connectors + wiring (free), check for vacuum leaks (cheap), replace sensor (moderate), replace mechanical part (expensive). Follow that ladder before dropping money on parts.
Manufacturer-specific descriptions
Different manufacturers use P0021 for slightly different failure modes:
| BMW | "A" Camshaft Position - Timing Over-Advanced or System Performance |
| MITSUBISHI | A Camshaft Position - Timing Over-Advanced or System Performance (Bank 2) |
| NISSAN | A Camshaft Position - Timing Over-Advanced or System Performance (Bank 2) |
Read P0021 on your own car
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