OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

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.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / numberC / 51

Possible causes

  • One float stuck on guide rod high
  • Saddle tank transfer pump failed medium

Inspection / repair

  • Difficulty: medium
  • DIY: shop recommended
  • Estimated cost: 200–1200 €
  • Estimated time: 1–5 h
  • Component: fuel level sensor a
  • Component: fuel level sensor b
  • Component: ecm
  • MIL / check engine light

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication