P0332

What it means

P0332 means the engine control unit has detected a low voltage signal in the circuit of knock sensor B, which is normally the sensor on bank 2 of the engine. The control unit saw the sensor signal sit below its expected range, so it cannot reliably detect knock or combustion vibration on that side. Which cylinders sensor B covers depends on the engine, so check the specific model layout.

Symptoms

• Check engine light on
• Reduced power or sluggish acceleration
• Poorer fuel economy
• Pinking or knocking under load, in some cases
• Rough running or hesitation
• Engine running with retarded ignition timing

Possible causes

• Damaged, chafed or corroded wiring to knock sensor B, including a short to earth or an open circuitlikely
• Poor connection or corroded terminals at the knock sensor B connectorlikely
• Faulty knock sensor Blikely
• Knock sensor loose or incorrectly torqued, giving a weak signalpossible
• Wiring damaged by heat, oil contamination or rubbing against engine componentspossible
• Fault in the engine control unit or its sensor reference supplyrare
• Outdated control unit software where the manufacturer has a known issue for the enginerare

How to diagnose

1. Read all stored codes and freeze frame data to see engine speed, load and temperature when the fault set, and note any other knock sensor codes.
2. Check the engine bay for oil leaks or previous repairs near the knock sensor, as the sensor is often under the inlet manifold on many engines (location varies by model).
3. Inspect the wiring and connector for knock sensor B for chafing, heat damage, oil ingress, bent pins and corrosion.
4. Check the sensor is fitted correctly and tightened to the manufacturer's torque, with no spacer or washer misfitted.
5. With the connector unplugged, measure the sensor circuit for short to earth, open circuit and resistance against the manufacturer's specification.
6. Check the sensor's own resistance or signal output against specification, tapping near it while watching live data if the procedure allows.
7. Check the control unit's reference voltage and earth at the sensor connector.
8. Check for a technical bulletin or software update relevant to the engine before condemning the control unit.

How to fix

• Repair or replace damaged wiring and ensure it is routed and clipped clear of heat and moving parts.
• Clean or replace the corroded connector or terminals.
• Replace knock sensor B and tighten it to the correct torque.
• Refit a loose sensor with correct torque and clean mating surface.
• Update the control unit software only if a known fault applies to this engine and the manufacturer supplies an update.
• Repair or replace the control unit only after wiring and sensor have been proven good.

Can I keep driving?

Nearby codes

• P0331GenericKnock/Combustion Vibration Sensor B Circuit Range/Performance
• P0333GenericKnock/Combustion Vibration Sensor B Circuit High