: 1996 DeVille Northstar

02-01-05, 03:20 PM
My service transmission message keeps coming on and the service engine soon light as well. I have had the car back to the dealer and they keep checking it and they say there is no transmission code showing. What could be my problem here. The car has 79000 miles and has been kept immaculately. It has the Northstar engine and it runs great, just this problem with the warning light. What's up, Help!!!:banghead:

02-01-05, 07:40 PM
dude im gonna move you to northstar area ....lets see if we can get you a awnser a little easier there ...that opens up your odds alot ....

02-01-05, 10:05 PM
Have you checked the codes yourself?

02-02-05, 11:15 AM
Did the dealership tell you what codes were in there? Without the codes, nobody will be able to tell you anything. You can check them yourself by holding down either the OFF and WARMER buttons or OFF and Passenger WARMER buttons. Be prepared to write them down quickly. They'll come up on the dash. They will be 6 character codes, such as PC0300 or RS0038, followed by either HISTORY or CURRENT. Make a note of all the codes and whether they're History or Current and let us know. Someone will chime in with some answers for you.

02-02-05, 03:15 PM
Thanks, I'll get back to you soon with the codes

02-04-05, 10:09 AM
Thanks for waiting, sorry it took so long. Here are the codes it shows.


When it gets to the end of the reading it comes up with PCM? What do I do here?

I really appreciate all of you guys advise.:worship:

02-04-05, 11:14 AM
Take a look at this thread:


02-04-05, 12:34 PM
Thanks, but what do I do with PCM?. I really appreciate all the help guys.:2thumbs:

02-04-05, 01:52 PM
Thanks, but what do I do with PCM?. I really appreciate all the help guys.:2thumbs:

Forgot about that, sorry... To exit the diagnostics, you can either just turn off the ignition or press OFF about 3 or 4 times until it goes back to normal display. The defrost button might also cancel out of it.

02-04-05, 05:19 PM
PCM? is asking if you want to enter the PCM mode. HI fan button = YES and the LOW fan button = NO. Once in the PCM mode you will get several options, one of which is CLEAR PCM CODES?. That's where you go to clear them.

02-07-05, 12:40 PM
Thanks, Ranger.

02-10-05, 09:43 AM
Is there anyway to reset the codes and the SES light?:confused:

02-10-05, 05:57 PM
Yes, see my post above.

02-10-05, 09:56 PM

I'm also experiencing the same 2 codes you are. I tried clearing the codes, didn't help.

A reply in my thread (96 Deville codes pco603 and pco717) indicates this problem has surfaced before and the Caddies have driven for two years with these messages.

Knock on wood.

02-11-05, 09:26 AM
I really appreciate all the help I have received here. You guys are great.

03-05-05, 10:12 PM
my 1996 deville had that also had a flashing oil light the prvouis owner spen $1600 fixing things at the dealership it very possiable that they are phantom codes or the senors of what ever the codes relate to are not bad enough yet good luck I hope there just phantom