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Technical Description of OBD-II Trouble Code
The knock sensor in cylinder 12 is detecting vibrations above the acceptable threshold.
Meaning of P2347
P2347 is a generic powertrain code that applies to many OBD-II vehicles (1996-newer), including Mercedes-Benz, Ford, Sprinter, Nissan, and others. The specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
If your vehicle has stored the code P2347 and the malfunction indicator lamp (MIL) is illuminated, it means that the powertrain control module (PCM) has detected a signal from the knock sensor in cylinder #12 that is outside the acceptable threshold.
The knock sensor is responsible for monitoring excessive vibration and noise in an individual cylinder or bank of cylinders. It uses a chemical reaction to detect engine knock caused by timing, detonation, or internal engine failure. The knock sensor reacts to changes in engine noise by increasing voltage. Since it is part of a low voltage circuit, any voltage changes are easily detected by the PCM.
If the PCM detects an unexpected level of voltage on the knock sensor circuit for cylinder twelve, it will store the code P2347 and illuminate the MIL. Multiple failure cycles may be required for the MIL to illuminate.
Severity of this DTC
When the code P2347 is stored, it is important to diagnose the cause as soon as possible. The symptoms associated with this code can range from minimal to catastrophic.
Symptoms of the Code
Symptoms of a P2347 trouble code may include:
Common Causes of the Code
The causes for this code may include:
Troubleshooting Steps for P2347
Ensure that the engine has the correct oil level and is in good working order. Eliminate any actual engine noise, such as spark knock, before diagnosing the code P2347.
To accurately diagnose the code P2347, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and reliable vehicle information.
Search for technical service bulletins (TSB) that match the stored code, vehicle information (year, make, model, and engine), and symptoms. This information can be found in your vehicle information source and may provide a quick solution to your diagnosis.
Connect the scanner to the vehicle diagnostic port, retrieve all stored codes and freeze frame data, and write down the information in case the code is intermittent. Clear the codes and test drive the vehicle until the code is restored or the PCM enters readiness mode.
If the PCM enters readiness mode, the diagnosis may be more difficult as the code is intermittent. The condition that caused the P2347 to be stored may need to worsen before an accurate diagnosis can be made. If the code is restored, continue with the diagnosis.
Use your source of vehicle information to obtain connector face views, connector pinout charts, component locator charts, wiring diagrams, and diagnostic flow charts specific to the code and vehicle in question.
Inspect the related wiring and connectors visually. Repair or replace any wiring that is cut, burned, or damaged. Replace spark plug wires and boots if the vehicle is beyond the recommended maintenance interval for a tune-up, as they may be the cause of the stored P2347.
Before removing the knock sensor, disconnect the PCM and use the DVOM to check continuity in the knock sensor circuit. Take caution to avoid getting burned by coolant or oil when removing the sensor. Test continuity through the sensor and back to the PCM connector.
Professional Service
We always recommend seeking professional mechanical assistance to solve this issue. However, if that is not possible, we offer the option to permanently delete this specific DTC while keeping all other codes active. If you are interested in this option, please upload your ECU file to our portal.
