Technical Description of OBD-II Trouble Code
Fueling Disabled – Misfire Detected
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to OBD-II equipped vehicles (such as BMW, Mini, Mazda, Ford, Hyundai, Chevrolet, etc.). Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
When I come across a stored code P0363, I immediately understand that the powertrain control module (PCM) has detected an ignition misfire and has disabled the fuel injector for the affected cylinder. I can also reasonably assume that the vehicle in question is of European origin.
The PCM monitors changes in the input signals from the crankshaft position sensor (CPS) and camshaft position sensor/s (CMPS) to determine if there is an ignition misfire and which cylinder is misfiring. Initially, when an ignition misfire is detected, the malfunction indicator lamp (MIL) may flash rapidly for a period of time and then stop instead of remaining illuminated. The purpose of the flashing MIL is to alert the driver that current driving conditions, combined with a cylinder misfire, could potentially damage the catalytic converter. Regardless of the flashing MIL, a misfire code should be stored, although it may be stored as a pending code.
In some vehicles, particularly of European origin, when the PCM detects multiple ignition cycles with a misfire code, it will disable fuel delivery to the affected cylinder. This is typically achieved by disabling the ground pulse to the fuel injector for that specific cylinder. Discontinuing fuel delivery to the particular cylinder is a good idea because excessive fuel can lead to catalytic converter failure. However, for novice technicians, this can also cause confusion during testing. The reason for this will be explained further in the troubleshooting section.
When an ignition misfire is detected, a cylinder misfire code is stored, and fuel delivery to the affected cylinder is disabled, a code P0363 will be stored and the MIL may illuminate. Usually, one or more cylinder misfire codes accompany this code.
Other misfire codes include P0300, P0301, P0302, P0303, P0304, etc.
Code Severity & Symptoms
A stored code P0363 is a reaction to one or more cylinder misfire codes, which should be considered severe.
Symptoms of this code may include:
Causes
Possible causes for this code to be set are:
Diagnostic and Repair Procedures
A good starting point is always to check for technical service bulletins (TSB) for your specific vehicle. Your issue may be a known problem with a known solution provided by the manufacturer, which can save you time and money during diagnosis.
To diagnose a code P0363, you will need a diagnostic scanner and an accurate vehicle information source (such as All Data DIY).
Since a code P0363 is essentially a reaction to a stored cylinder misfire code, you will need to diagnose any stored cylinder misfire codes (P0301 through P0312) before attempting to diagnose this code. While there are many tools designed to test ignition coil, spark plug, and fuel injector function, I have found the simple method of swapping components between cylinders to be effective for many years. This may not always be possible with fuel injectors, but it works well with ignition coils and spark plugs, which tend to fail more frequently than fuel injectors. For more tips on diagnosing cylinder misfire codes, refer to the appropriate entry in OBD II Codes.
You will still need the scanner to retrieve stored codes and freeze frame data. The scanner is also used to clear codes after you have written them down for reference as the diagnostic process continues. Once you have completed these steps, clear the codes and you can begin swapping components for testing purposes. It is important to replace spark plugs in sets if the vehicle is near the recommended replacement interval. However, locate the malfunctioning part before performing any maintenance. When replacing an ignition coil for a particular cylinder, it is recommended to replace the spark plug as well (unless the spark plugs have been recently replaced). This will save time in the long run.
The problem that often causes confusion is that when some technicians discover that there is no ground pulse to the injector for the cylinder in question, they treat it as a malfunction instead of a reaction caused by the PCM to an ignition misfire. This can lead to a wild goose chase if you are unfamiliar with the fuel disabling system used in certain models.
If the P0363 code is stored without any cylinder misfire codes, suspect a defective PCM or a PCM programming error.
Additional diagnostic notes:
