Hi all,
I'm hoping to gain some info and insight on a situation my son just went through today. His 95 2500 CTD failed the emissions test due to the "check engine light" NOT coming on when the key is turned. The emissions tech said he wasn't going to test the truck because with the light NOT coming on it already failed. Has this happened to anyone?

 

Either the bulb is burned out, or the PCM is fried. Does it shift into Overdrive? TCC engage? (is it even an automatic?)

 

Does the multifunction switch turn this on or something about CTM?

 

Thx for replying, this truck is a 5 speed manual.

 

95 CTD, and a manual trans? Ok, so just what does the PCM DO in that truck? It doesn't run the engine, that's all mechanical, it doesn't run the trans either....... Seems to me, you could REMOVE the PCM, and the truck wouldn't notice.........

 

if the bulb is good maybe you just tie the it into the oil pressure circuit so that the light will stay on till you start turning the engine over and building oil pressure. just an idea. or maybe hook it up to the seat belt light if that work.

i agree with heyyou about the pcm. it most likely aint doing a single thing. it only take about 3 wires to run a diesel engine.

 

Problem found and resolved. My son found the bulb bad. I thought it was odd that it would fail emission because of this bulb. Thanks for reading and giving your thoughts.