Help Find My "Check Engine" Light Circuit
 

Didn't pass my emissions check because my "check engine" light was not operating. I want to trace the circuit to try to find the problem but can't find the light in my Chiltons manual. I do find a light called "malfunction indicator lamp". Is that the same as the "check engine light"? It's in the section of the electrical schematic named Instrument Panel Warning System. According to the schematic, it is a pink/light green wire going into the PCM. I have read that the "check engine light" is a ground functioning circuit to where the PCM completes the ground circuit when it finds a problem. Is this correct? The truck is a 1997 F150.

The malfunction indicator light is the check engine light. But before I would check wiring I would see if the bulb is burnt out or missing. I work at a car lot and it does happen more than you would think

Check the fuse also. It is a 5 amp fuse that sometimes will blow out. The OBD port will not read, if the fuse if blown. Good luck.