CEL is MIA

[cjaygo]

I purchased this 93 SHO auto approximately a year ago. Just this week i noticed that my check engine light does not illuminate when i first turn the key to start the car. I'm thinking that the original owner may have somehow disconnected it. Does anybody have any sugestions on what to look for or where to start?

 

[projectSHO89]

Uh, check the light bulb first....

 

[DJ SHO]

It either burned out, or someone pulled the bulb. You'll have to pull the instrument cluster to find out.

<small>[ May 21, 2003, 04:17 PM: Message edited by: DJ SHO ]</small>

 

[projectSHO89]

Or there is an open line between the instrument cluster and the PCM or a defect in the PCM.

Quick test:

Locate the self-test connector under the hood. Identify the pin that has two Tan/Red wires going to it. Connect a jumper from this pin to ground. Briefly turn the ignition key to RUN whil watching the CEL.

If the CEL lit, the problem is either the PCM or an open circuit between the PCM and the self-test connector.

If the CEL did not light, there is either an open circuit between the self-test connector, the buld is defective or missing, or there is a fault on the printed wiring board in the instrument cluster.

Steve