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P2338 is a diagnostic trouble code (DTC) for "Cylinder #3 Above Knock Threshold". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
A P2338 code is a generic powertrain code related to an ignition-related problem, such as an engine misfire. It appears when the engine control module (ECM) has received a voltage reading outside the allowed variances from engine cylinder number three.
The P2338 code may be related to:
A knock sensor is a one-wire sensor that helps the engine control module (ECM) “hear” engine noise to help determine proper function through the use of a low-voltage signal. When the ECM receives a voltage reading from the knock sensor in cylinder 3 that varies 10% or more from the set voltage parameters, a P2338 code will be stored. If an abnormal reading is received by the ECM, it can adjust engine timing to reduce possible damage.
A P2338 code can be caused by:
Because the knock sensor is essentially a microphone for the engine, it is possible that a sensor may be “hearing” an issue with a different cylinder and storing an inaccurate code. Ensure that all cylinders are checked for possible damages before returning to the road.
Since a vehicle’s knock sensors can decrease acceleration, this can impacting drivability and may possibly signify a more serious problem. This is considered a potentially serious code and it is recommended to have the vehicle immediately diagnosed and repaired.
As not all knock sensors are easy to access, so test and diagnose all other sensors to avoid unnecessary engine removal or repair. Also, ensure that care is taken when removing knock sensors, as the coolant passage can cause severe burns.
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.