Malfunction Indicator Lamp (MIL)
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
The MIL notifies the driver that the powertrain control module (PCM) has detected an OBD emission-related component or system fault. When this occurs, an OBD diagnostic trouble code (DTC) will be set.
- The MIL is located in the instrument cluster and is labeled CHECK ENGINE, SERVICE ENGINE SOON or the ISO standard engine symbol.
- The MIL is illuminated during the instrument cluster prove out for approximately 4 seconds.
- For applications with a dedicated hard wire MIL circuit, the PCM will illuminate the MIL until a profile ignition pickup (PIP) signal is detected. For 2005, the following vehicles use a hard wire circuit: Crown Victoria/Grand Marquis, Explorer Sport Trac, and Ranger.
- The MIL will remain illuminated after instrument cluster prove out if:
- an emission related concern and DTC exists.
- no PIP signal is detected (applications with a dedicated hard-wire MIL circuit). The PIP signal is generated in the PCM using the crankshaft position (CKP) sensor. For these applications, the MIL can be helpful in diagnosing a no start.
- the PCM does not send a control message to the instrument cluster (applications with the MIL controlled through the communication link).
- the PCM is operating in the Hardware Limited Operation Strategy (HLOS).
- the MIL circuit is shorted to ground (applications with a dedicated hard wire MIL circuit).
- The MIL remains off during the instrument cluster prove out if:
- an indicator or instrument cluster concern is present.
- the MIL circuit is open (applications with a dedicated hard wire MIL circuit).
- To turn off the MIL after a repair, a reset command from the diagnostic tool must be sent, or 3 consecutive drive cycles must be completed without a fault.
- For all MIL concerns, go to SYMPTOM CHARTS - GASOLINE MODELS .
- If the MIL flashes at a steady rate, a severe misfire condition may exist.
- If the MIL flashes erratically, the PCM can reset while cranking if the battery voltage is low.