What does the fault code P031300 for Mercedes-Benz mean?
2 Answers
Mercedes-Benz fault code P031300 indicates that a combustion misfire was detected when the fuel level signal was activated. Diagnostic fault: The diagnostic found that the engine has fault code P031300, which means a combustion misfire was detected when the fuel level signal was activated. Actions taken: During the test drive, engine shaking was observed, indicating a misfire in cylinder 1. Following the guidance of the fault code, operational tests were performed. The power supply end of the ignition coil for cylinder 1 measured 12 volts, and the ground wire had a resistance of 0.2 ohms to ground, indicating the debugging was complete. An attempt was made to swap the ignition coils and spark plugs of cylinders 1 and 2. The ignition waveform for cylinder 2 then appeared normal, confirming the debugging was successful. Fault resolution: No fault symptoms were found.
Seeing the P031300 fault code on your Mercedes indicates an ignition issue in one of the engine cylinders. Specifically, it points to a misfire in cylinder 13—though the engine doesn’t actually have that many cylinders, likely due to system numbering. The most common culprits are aging ignition coils or carbon buildup on the spark plugs, but clogged fuel injectors or insufficient fuel pump pressure could also be to blame. Symptoms include the engine shaking like a massage chair and sluggish acceleration. My advice? Shut off the engine immediately and check the freeze frame data from the fault code. Prioritize inspecting the ignition coil for cracks or leakage in the affected cylinder, and pull the spark plug to check for excessive gap. Don’t delay repairs—otherwise, the catalytic converter could end up burnt to a crisp. A repair shop can use an oscilloscope to measure the ignition waveform and pinpoint the culprit.
