Malfunction Indicator Light
The "Malfunction Indicator Light" (MIL) will be illuminated under the following conditions:
- Upon the completion of the next consecutive driving cycle where the previously faulted system is monitored again and the emissions relevant fault is again present.
- Immediately if a catalyst damaging fault occurs.
The illumination of the light is performed in accordance with the Federal Test Procedure (FTP) which requires the light to go on when:
- A malfunction of a component that can affect the emission performance of the vehicle occurs and causes emissions to exceed 1.5 times the standards required by FTP.
- Manufacturer-defined specifications are exceeded.
- An implausible input signal is generated.
- Catalyst deterioration causes HC-emissions to exceed a limit equivalent to 1.5 times the standard (FTP).
- Misfire faults occur.
- A leak is detected in the evaporative system, or purging is defective.
- PCM fails to enter closed-loop oxygen sensor control operation within a specified time interval.
- Engine control or automatic transmission control enters a limp home operating mode.
- Ignition is in on position before cranking = bulb check function.
A fault code is stored within the PCM upon the first occurrence of a fault in the system being checked. The Malfunction Indicator Light (MIL) will not be illuminated until the completion of the second consecutive "customer driving cycle" where the previously faulted system is again monitored and a fault is still present or a catalyst damaging fault has occurred. If the second drive cycle was not complete and the specific function was not checked, PCM counts third drive cycle as "next consecutive" drive cycle. MIL is illuminated if the function is checked and the fault is still present. See Fig 1.
If there is an intermittent fault present and does not cause a fault to be set through multiple drive cycles, 2 complete consecutive drive cycles with the fault present are required for MIL to be illuminated. Once MIL is illuminated it will remain illuminated unless the specific function has been checked without fault through 3 complete consecutive drive cycles. Fault code will also be cleared from memory automatically if specific function is checked through 40 consecutive drive cycles without the fault being detected or with the use of either DISplus, GT-1 or scan tool. In order to clear a catalyst damaging fault from memory, the condition must be evaluated for 80 consecutive cycles without the fault reoccurring.