Check Engine Light not working

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dartslantsix

dartslantsix

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So I've got my engine running, and I wanted to check for trouble codes. For some reason the check engine light pin is not working.
Today I checked for continuity through the 60 way connector and it's good.
I know that the pin provides a ground, so I was checking by looking for continuity to ground while the key was on. Nothing.

What could cause this? Anything besides an internal PCM issue? I did remove the diagnostic plug from the wiring. I'm not sure if this would effect the check engine light.

This is a 1994 OBD I system swapped into my 67 Barracuda. No actual light is hooked up yet, I'm using my test light directly connected to the PCM.

Thanks.
 
The light should come on with the key as a bulb check.. The bulb itself may be burned out. You can only hope. Then depending on the brand and model, it should flash code 12 when the correct 2 pins are connected to each other. I can 't remember for sure which two on the GM cars. That was 30+ years ago. The Internet should tell.
One of my 96 Dakota's had the bulb in and working but the cavity was jammed full of strip caulk. Aparently the previous owner got tired of looking at the light.
 
67Dart273 said:
How do you know it SHOULD be on?
Click to expand...
The engine is not running quite right and I wanted to check the trouble codes. This would be the fastest way to diagnose the problem.

I did test the TPS separately and found it to be faulty. I suppose I could test each sensor, but it would be easier if the check engine light pin was working.

I edited the initial post to add that this is a 94 magnum swapped into my Barracuda.
 
It shouldnt have continuity to ground, it goes to the bulb in dash, not a ground buss. If you want to test it, get a test light, hook the clamp to the CEL pin and the other end to batt +. It should turn on the light when key is on. It will not flash codes unless you put it into code reading mode. You can either flash code via light w ten code flash or you can scan it with OBD I code reader which is more accurate .
 
magnummopar said:
It shouldnt have continuity to ground, it goes to the bulb in dash, not a ground buss. If you want to test it, get a test light, hook the clamp to the CEL pin and the other end to batt +. It should turn on the light when key is on. It will not flash codes unless you put it into code reading mode. You can either flash code via light w ten code flash or you can scan it with OBD I code reader which is more accurate .
Click to expand...

Another way to test it might be to attempt to put the ECU into the code read mode
 
If it doesnt light with key on, it probably wont light during code check. Thats why I recommended the test light method to make sure the pcm is throwing a CEL or has some internal issues
 
Well, somehow it started working today.
I unplugged the PCM connector and made sure it was fully seated and I was able to get codes out of it.

Unfortunately, none of the codes help me. I think I'll need to drive it more for more codes to set. Idle seems high (don't have a tach yet) and it still stumbles a little at throttle tip in. Cold start is rough too.

12 battery disconnect
33 a/c clutch
31 evap purge
32 EGR not working
55 end of codes
 
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