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

P2340

Cylinder 5 Above Knock Threshold

The knock-sensor evaluation reports cylinder 5 above the knock threshold over a sustained window. The ECU retards ignition for that cylinder; persistent knock indicates poor fuel quality, carbon deposits or cooling issues.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number3 / 40

Possible causes

  • Low octane or contaminated fuel high
  • Carbon deposits raise compression locally medium
  • Local cooling issue at cylinder 5 low

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 50–600 €
  • Estimated time: 0.5–4 h
  • Component: knock sensor
  • Component: cylinder 5
  • 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