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

P0321

Ignition/Distributor Engine Speed Input Circuit Range/Performance

Engine speed input from the ignition/distributor is in electrical range but plausibility check fails — slow response, drift, or noise.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number3 / 21

Possible causes

  • Sensor drift or pickup gap wrong high
  • Sensor element aged beyond calibration window low
  • Sensor mounting loose - signal damping low

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 80–600 €
  • Estimated time: 0.5–2.5 h
  • Component: ignition distributor
  • 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