P0331

Knock Sensor 2 Circuit Range/Performance (Bank 2)

Car Fault Codes Ignition & misfire

Severity Medium Do not ignore it; it may get worse and cost more.
Can you still drive? With care, short trips only
Who can fix it? Needs a workshop
Typical repair time 30 minutes – 4 hours
Typical cost SAR 100 to 900

What it means

The knock sensor 2 circuit on bank 2 is electrically connected, but the engine computer finds that its signal does not match engine conditions, or differs widely from the bank 1 sensor. The cause may be the sensor or its mounting, or real noise on the bank 2 side of the engine.

Symptoms4

  • Check engine light on.
  • Reduced performance from retarded ignition timing.
  • Pinging from the engine under load in some cases.
  • Higher fuel consumption.

Possible causes6

  • Weak or internally damaged sensor.
  • Sensor tightened to the wrong torque, or rust or dirt beneath it.
  • Mechanical noise on the bank 2 side, such as a loose part or valve noise.
  • Real detonation in bank 2 cylinders from low-octane fuel or carbon deposits.
  • Electrical interference on the sensor wiring.
  • Corroded connector weakening the signal.

How to diagnose5

  1. Listen to the bank 2 side of the engine for mechanical noise or pinging.
  2. Confirm the fuel grade and that engine temperature is normal.
  3. Check the sensor mounting and torque against the manufacturer specification.
  4. Inspect the connector and wire routing.
  5. Compare the sensor 2 signal with sensor 1 on an oscilloscope; a large difference points to sensor 2 or its mounting.

How to fix6

  1. Use the recommended octane fuel.
  2. Clean the mounting surface and retighten the sensor to the correct torque.
  3. Repair any mechanical noise source on bank 2.
  4. Repair the connector or wiring.
  5. Replace knock sensor 2 if it is proven weak.
  6. Clear the codes, drive under moderate load and confirm the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

A fuel change or retightening may be enough at little cost; the cost rises with a new sensor, especially in a hard-to-reach spot.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions

Why is the code only for bank 2?

Sensor 2 monitors only the bank 2 cylinders, so noise, a mounting problem or knock near it shows in its reading and not in sensor 1.

Should I replace both sensors?

Not if sensor 1 is fine and has no code, unless both are old and reaching them requires the same disassembly.

This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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