P2C51
Fuel Level Sensor A/B Correlation
The signals of fuel level sensors A and B do not correlate within the calibrated tolerance. Common in saddle tanks where two sensors monitor each tank half.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- One float stuck on guide rodCommon
- Saddle tank transfer pump failedPossible
Parts involved
- Fuel Level Sensor A
- Fuel Level Sensor B
- ECM
P2C51 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.