Malfunction Indicator Light (MIL)

MIL may also be referred to as Service Engine Soon light. If all systems are normal, immediately after ignition switch is turned on, MIL will illuminate for 5 seconds, then go out. When ECM/PCM determines an emissions related malfunction exists, ECM/PCM will turn the MIL on. If ECM/PCM determines that the malfunction no longer exists, it will turn the MIL off.