Skip the auto shop - Our mechanics make house calls

P0331 OBD-II Trouble Code: Knock Sensor 2 Circuit Range/Performance (Bank 2)

P0331 OBD-II: Knock Sensor 2 Circuit Range/Performance (Bank 2)

Diagnostic Trouble Code (DTC): P0331

P0331 code definition

A P0331 code is stored when the powertrain control module (PCM) determines that an engine pre-detonation (knock or ping) has an abnormally high noise level or that it is out of the ordinary in some other way.

What the P0331 code means

Knock sensor 2, on engine bank 2, is designed to detect engine knocks or pings. This two-wire sensor sends a signal to the PCM to inform it of any instances of knocks or pings and how severe they may be. This input on normal knocks and pings allows the PCM to predict engine pre-detonation and account for it to predict knock trends and slow spark timing as necessary. If a knock or ping is too loud or too far out of the ordinary, the P0331 code will be saved, and the Check Engine light or MIL (Malfunction Indicator Light) will be illuminated.

What causes the P0331 code?

There are a few different causes for a P0331 code to be stored, including:

  • Using the incorrect fuel octane
  • A damaged knock sensor connector
  • An open circuit to the knock sensor
  • A knock sensor circuit that’s shorted to ground or voltage
  • A faulty knock sensor
  • Moisture in the knock sensor’s connectors
  • A faulty PCM (rare)

What are the symptoms of the P0331 code?

Noticeable symptoms when a vehicle has a stored P0331 code include:

  • An illuminated Check Engine Light or MIL
  • A pinging from the engine upon acceleration
  • An audible knocking coming from the engine

How does a mechanic diagnose the P0331 code?

When a mechanic diagnoses the problem causing a P0331 code to be stored, they will first listen to the engine while it’s running to determine if there is a knock or if the problem is more likely an issue with the sensor. After listening to the engine and visually inspecting it, they’ll address the issue causing the knock, clear the code, and retest to ensure that the sensor is not malfunctioning and there aren’t any other problems.

If there is no audible knock or the code is stored again after fixing the knock, the mechanic will unplug the knock sensor to inspect for corrosion or moisture in the connector. They will then take the proper diagnostic steps to address any issues with the knock sensor and retest the code again.

How serious is the P0331 code?

A knocking engine is at risk of leaving you stranded on the side of the road. If you hear a deep knocking in your vehicle, it could be an indication that the rod bearings are worn and in danger of seizing. If your vehicle has stored a P0331 code because it has a malfunctioning knock sensor, the PCM will not be able to adjust for engine knock, and further engine damage can occur.

What repairs can fix the P0331 code?

A P0331 code may be fixed by simply cleaning corrosion from the knock sensor’s connectors and ensuring that there is no moisture in the connectors. Other possible repairs include:

  • Using the proper octane for the vehicle and/or using an octane booster
  • Cleaning out carbon deposits in the engine’s cylinders
  • Replacing the spark plugs
  • Repairing or replacing the rod bearings
  • Repairing or replacing the knock sensor
  • Repairing or replacing the wiring and connectors for the knock sensor’s circuit

Additional comments for consideration regarding the P0331 code

In addition to other problems that may occur due to a persistent abnormal engine knock and/or a faulty knock sensor, failing to diagnose and clear a P0331 code will make it impossible to pass an OBD-II emissions test, as the MIL or Check Engine light will be illuminated until the problem is resolved.

Need help with a P0331 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...


Related questions

Q: On slow moving traffic, when i release the brakes, the car has lags for half a second before take off... computer scan shows p2138

This code is related to a faulty throttle position sensor. The throttle position sensor (TPS) is a sensor used to monitor the throttle position of a vehicle. The sensor is usually located on the butterfly spindle/shaft so that it can...

Q: Car died after battery, brake, and Check Engine light came on.

Hi there. When you get this combination of warning lights and symptoms it is typically the result of a battery that has failed. If the battery voltage gets low enough then the check engine light and the brake light can...

Q: Brake problems

Although I'm not there to inspect your Ford Super Duty, it would seem logical to inspect your Electronic Brake Control Module (EBCM). This component reads all of the braking system’s sensors and activates the ABS or traction control system when...