Updated: Feb 4
✔ This article has been fact checked.
If the knock sensor 2 circuit outputs a low input signal, the PCM (powertrain control module) will register a P0332 fault code, potentially triggering a check engine light.
A P0332 code is a sign of a potentially serious problem and may cause engine damage if left unfixed, avoid driving the vehicle if this code appears and fix as soon as possible.
If a DTC is associated to the powertrain, an OBD scanner will read it as starting with P, thus the letter "P". Generic fault codes are those of the format P0xxx.
Table of Contents:
The Meaning of a P0332 Fault Code
P0332 is a diagnostic trouble code (DTC) which stands for "Knock Sensor 2 Circuit Low Input (Bank 2)".
The knock sensor's function is to alert the PCM when the engine knocks (when the air/fuel mixture combusts prematurely).
If the PCM receives an incorrect knock sensor reading, it will be unable to correctly deliver the necessary adjustments to the engine. This may lead to a variety of issues.
Is It Serious?
Engine knocking may significantly impair an engine's ability to function cleanly and effectively and may even cause damage to engine components if it's left unfixed.
If the knock sensor fails to work properly, the PCM will be unable to properly adjust the engines performance based on the knock sensor data. This might result in a rough-running engine, overheating, lower fuel economy, and other potentially issues.
This is especially important if your vehicle is high powered, turbocharged, supercharged, or is tuned / remapped.
When knocking occurs in the engine, there is also an excessive amount of NOx that is released, causing the vehicle to fail emissions testing.
It's recommend not to drive your vehicle until this issue is fixed.
Signs & Symptoms
In some rare circumstances, the only indication is the check engine light turning on.
You may notice the following signs:
Check engine light (CEL) illumination
The ECM may trigger failsafe mode (limp mode) in which the engines power will be reduced
Knocking in the engine may occur while accelerating, you may even hear or feel this.
The engine may overheat, even while driving normally.
A loss of engine performance and power.
Over time other issues may arise, resulting in more signs and symptoms.
Oftentimes the knock sensor itself is the issue. However, the following may also cause a P0332 fault code.
A cooling system malfunction
An unusually lean air/fuel ratio
A problem with the knock sensor circuit or one of its connections
EGR (exhaust gas recirculation) system failure
Diagnosing the P0332 Trouble Code
You or a technician should follow the steps below in order to diagnose a P0332 code.
Begin a visual evaluation of the sensor and its circuit after validating the code with an OBD scanner.
Next examine the circuit, connections, and other associated components using an ohmmeter and other diagnostic equipment.
Clear the code from the PCM and retest the system by turning on the car after each test or repair.
Conduct a test drive to confirm that there is no intermittent issue that has to be resolved.
It's important to properly diagnose and validate the P0332 error code. In some circumstances, the wiring or connections is the issue and not the knock sensor itself.
Sometimes the problem may be with the cooling system or the EGR system, in which case replacing the knock sensor would not resolve the issue.
Potential Fixes for a P0332 Fault Code
If this fault code has appeared used a professional OBD scanner and P0332 has been verified as the actual issue you should take the following steps to fix it.
Technical service bulletins (TSB) may provide useful diagnostic information which can help you diagnose and fix the issue.
In the sensor circuit, replace frayed or damaged wires and connections.
Make certain that the knock sensor and the circuit are properly grounded.
Make that the knock sensor voltage is within the specified range.
Check the voltage of the temperature sensor to confirm that it is within the required range. If not, the temperature sensor may be delivering incorrect readings to the PCM, resulting in a lean operating state and engine knock. Replace the temperature sensor and wire if that is the issue.
Replacing the knock sensor may be required if the previous fixes did not work.
Rarely you may need to replace or reprogram the PCM, or replace the EGR or cooling system.