CEL Presence

Weather permitting, I'll be under the dash this weekend cleaning up some prior owner wiring "projects" and installing a intermittent wiper switch I picked up, along with being under the hood for the fast idle flummox.  While I'm in there  I'll be looking for the infernal inferred mileage sensor that shows up in my EVTM and report back.

EDIT:  In looking at my EVTM, the IMS has a detail note that matches Gary's info limiting these to 5.0L CA engines only.  It may  still be there since my VIN indicates it come off the line with that engine.

From the EVTM, it appears powered by the EEC relay, but may be easier to track back from the battery's dedicated negative terminal wire.

Mark/Dyn Blin emailed me with some links to information about the inferred mileage module as well as the emissions maintenance warning module.  And, one of those links led to TSB 89-22-08 EMW/IMS Applications, which is now included on the page TSB's/Emissions Maintenance Warning Module.  Have a look and see what its info does to/for this discussion.  

Thanks, Mark!  

My pleasure,

IT would seen to put an (unsatisfactory) end to the question of when the IMS started to make the "EMISSIONS" lamp engage...

 It never did...