P0332
PowertrainKnock Sensor 2 Circuit Low Input (Bank 2)
You'll usually notice this one as a warning light first, maybe with the engine feeling a bit flat under load or pinging on a hill. The knock sensor on Bank 2 listens for the metallic rattle of detonation and tells the ECU to pull timing when it hears it. When that sensor's signal comes back lower than the ECU expects, it stops trusting the reading, runs a more conservative ignition map to be safe, and sets P0332. So the engine protects itself, but you lose a bit of performance and economy while it does.
ⓘ Information only. This page provides general educational information about fault code P0332. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0332 mean?
P0332 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Knock Sensor 2 Circuit Low Input (Bank 2).
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine management light on, often the only thing you'd notice
- • A metallic pinging or rattle under acceleration, worst when labouring up a hill or pulling away with a load
- • Sluggish, flat feeling under load as the ECU retards the timing to play safe
- • Fuel economy creeping up, more obvious on a regular commute than a one-off run
- • Slight hesitation or a brief flat spot when you put your foot down
- • Occasionally a rougher idle from cold that settles once it's warm
Possible causes
Causes commonly associated with P0332, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. The knock sensor itself failed internally on Bank 2. These are piezo sensors and they do degrade with age and heat, this is the usual culprit
- 2. Corroded, chafed or broken wiring in the sensor circuit, very common where the loom runs in the valley of a V6 or V8
- 3. A poor connection or moisture in the sensor plug, the connectors sit in a hot dirty spot and don't always stay sealed
- 4. A dodgy earth for the knock sensor circuit giving a weak signal back to the ECU
- 5. Water collecting in the valley under the intake manifold, a known issue on some V6 and V8 layouts where the sensor sits in a well that fills up
- 6. A faulty ECU, but that's rare and the last thing to suspect
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Read the full code list, not just P0332. If you've also got P0327 or P0330-series codes, that points more at wiring or a shared earth than one dead sensor
- 2. Get eyes on the sensor connector and harness. On a V engine that often means lifting the intake manifold, but you're looking for green corrosion, water, chafed insulation or a loose plug
- 3. Back-probe the circuit with a multimeter and check continuity and the earth back to the ECU against the workshop spec. A high-resistance earth will drag the signal low and trip this code
- 4. With wiring proven good, test the knock sensor's resistance and compare to the manufacturer figure. Out of spec, replace it
- 5. Clear the code and drive it under a bit of load to see if P0332 comes straight back or stays away
Common questions about P0332
Should I just buy a cheap sensor off eBay or pay for a proper one? +
Spend the bit extra and get a genuine or quality branded part like NTK, Bosch or Delphi. Knock sensors are fussy about their signal, and cheap no-name ones are a known cause of the code coming straight back or never clearing in the first place. If you've gone to the trouble of dropping an intake manifold to reach it, the last thing you want is to do it all again because a £12 sensor reads wrong. The good ones aren't expensive, usually £30 to £70 for the part.
Can I keep driving like this for a while? +
For gentle local driving you'll be fine, the engine has put itself in a safe timing map specifically to avoid harm. The risk is when you load it up, towing, motorway hills or a fully loaded car, because the ECU can no longer hear genuine knock on that bank and detonation does real damage to pistons and bearings over time. So drive it, but go easy and book it in rather than ignoring it for months.
Is this going to fail my MOT? +
The code on its own isn't a fail. What catches people out is the engine management light being on at the time of the test, which is itself a fail on the emissions and warning light check. Fix the cause, clear the light and run a couple of drive cycles so it stays off before you take it in. A car that's pinging and running rich can also struggle the actual emissions readings, so it's worth sorting first either way.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →