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

P0177

Fuel Composition Sensor Circuit Range / Performance

The flex-fuel composition sensor signal is within electrical limits but does not match expected values for the current fuel mix or rate-of-change is implausible.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 77

Possible causes

  • Sensor drifted out of calibration high
  • Fuel contaminated (water, dirt) medium

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 120–500 €
  • Estimated time: 0.5–2 h
  • Component: flex fuel composition sensor
  • MIL / check engine light
  • emissions-relevant

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