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

P0325

Knock Sensor 1 Circuit Malfunction (Bank 1)

A general fault has been detected in the bank 1 knock sensor circuit. The ECU uses the knock sensor to detect pre-ignition and retards ignition timing when knock occurs; with no signal, the ECU runs conservative timing and loses power.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number3 / 25

Possible causes

  • Knock sensor failed high
  • Sensor mounting bolt loose (sensor must be torqued correctly) medium
  • Wiring fault low

Symptoms

  • Check engine light on
  • Power loss from defensive spark retard
  • Increased fuel consumption
  • Possible audible pinging under load

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 200–800 €
  • Estimated time: 1.5–6 h
  • Component: knock sensor
  • Component: knock sensor wiring
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required

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