: PCM Overrides?

12-11-04, 10:03 PM
I've seen references in various places on the web and heard from other people with Northstars that when they go into the DIC diagnostics PCM section, they have entries for PCM DATA, INPUTS, OUTPUTS, and/or OVERRIDES. On my 96 SLS, I only see PCM CODES and PCM CLEAR CODES. Is there some reason why I can't see the other goodies? Perhaps it's not available on a '96, or not on analog cluster cars? Is it something that has to be enabled with one of the IPC overrides, or is there some super-secret button sequence or engineer handshake you have to do to enable it? I'm just curious, it's not a problem.


12-11-04, 10:16 PM
It was not available on a 96 or later due to OBD2. The federal requirements for OBD2 commonized the diagnostic codes, readouts, OBD access, etc... The PCM override and other functions were not in compliance with the OBD2 regulations so they were discontinued. You'll have to buy a 95 or older car to have a non-OBD2 car with the PCM overrides.

12-12-04, 10:59 AM
I figured it would be something like that... Thanks very much for the info, Bbob!



12-14-04, 04:07 PM
I have a 1996 ETC. I believe that I saw overrides and data?
Do I have a 1995 computer? Is my car OBD II or OBD I.
Is there any way to tell?

12-14-04, 07:56 PM
I have a 1996 ETC. I believe that I saw overrides and data?
Do I have a 1995 computer? Is my car OBD II or OBD I.
Is there any way to tell?

If you have a 96 car you do not have a 95 computer....no way possible for it to work.

Your car, by federal law, is an OBD2 car....no exceptions. That is how you tell. OBD2 requirements took effect beginning with the 96 model year.

I doubt that you saw PCM overrides or data.. The OBD requirements just apply to the engine/emission control system. That is the overrides and such that reverted back to using a Tech tool to access them. There are no OBD requirements for accessories and secondary systems on the cars. Therefore you will still see overrides, data parameters and such for the other systems like the IPC, TCS, RSS.....

The onboard displays can still display the trouble codes and be OBD2 compliant so that part was left in for the PCM but any of the other onboard diagnostic functions for the PCM were discontinued and must be accessed via the Tech tool.

STS 310
12-15-04, 01:29 PM
I know you can enter the PCM interface for somethings ( I dont know). It is possible that you saw "PCM?" or "IPC?". You are able to change some things this way but I dont the extent. I have only used the IPC to change values to the DIC to get the temp reading digitally. :D

12-15-04, 05:11 PM
What the purpose of overiding? I dont know what the code are.

12-16-04, 01:48 AM
It is used mostly to help you diagnosing problems.

For example you can command the ISC (Idle Speed Controller) motor to extend or retract. Or turn the cooling fans on in lo or hi speed. Or, turn the AC clutch on. Or turn off a fuel injector. Stuff like that.

Today's cars are pretty much "computers on wheels" and you need this kind of functionality to be able to fix them.


12-17-04, 11:09 AM
It would be fun to tinker around with those settings, as long as they're not permanent, just to test things if the need arises. Since they don't appear on 96 or later cars, I guess I'm just SOL, which means Sadly Out of Luck.

07-30-07, 10:25 PM
I know this is old, but I wanted to post. I have a 1996 ETC.
I do have the data, inputs, outputs, overrides. IPC does have overrides. I have been in the section, but don't understand as the labels and numbers don't make sense.

07-30-07, 11:03 PM
you dont have a 96 then...

07-31-07, 09:50 AM
You're going to need a FSM to decipher all that.

05-10-09, 08:20 AM
How to go to PCM OVVERRIDE with a cadillac sts 98 (OBD2).

I think I can i go with a tech 2?

There are a another scanner or metod that allows less expensive to go to PCM OVVERRIDE?

thank you

05-10-09, 09:48 AM
Can't be done. Read your parallel post next to this thread.

Mark C
05-10-09, 11:14 AM
I have overrides, data, etc on my 97 STS for other controllers, like the IPC but not for the PCM. Just been afraid to change any of the settings.

05-13-09, 07:25 AM
If you have the FSM you can do all kinds of neat things with the other overrides / data sections of the other non-PCM overrides sections. Like change your country code, which for me alters the speedo needle position, and no it doesn't put it in K/h, I've actually changed it on the fly on the highway and watched my needle jump 20 MPH lower when I alter country codes. I still haven't tested, though I should, to see if it gets you around the limiter (mine is non the Z so 130MPH is all I got). Only problem is I need my buddy's GPS to verify, and a very long section of road, maybe I'll do it when I dyno the track car, that'd be fun. I'm just talking out loud, but yea, get the FSM and read the sections with what you can do with it. There are tons of features buried in there and it's neat to root around in it, just familiarize yourself on what your factory settins are before you start modifiying things so you can go back...

02-24-12, 02:13 PM
where do i find the FSM?!

02-24-12, 02:39 PM
where do i find the FSM?!

Old acronym for Factory Service Manual, now generally "Service Manual". Get the real thing (GM publication) off eBay or from www.helminc.com (http://www.helminc.com). Chilton and Haynes are essentially useless - far, far too generic.

You might consider a subscription to www.alldatadiy.com (http://www.alldatadiy.com).

..............and if you're looking for a way to get into your 1998 or 2000 PCM, you won't find it in the service manual. Your owner's manual has a lot on Personalization.....

02-24-12, 03:05 PM
Sub, I think he is asking where he would find the override info in the FSM.

The answer is you won't. Not in a '98 manual. If I am not mistaken, overrides went away with OBDII in '96.

Mark D
03-03-12, 01:47 PM
Remember that although oBD-II came out in 1996, it was not mandatory across the board until 1997. The 1996 cars can be either, depending on mid-year changes and on when the manufacturer decided to go to OBD-II with that particular model. Some OBD-II 1996 cars can be pretty difficult to diagnose because they are a sort of quasi-OBD-II.
If Carguy up the list says his '96 has the full diagnostics, then I would take him at his word. He knows his car better than anyone on this forum, since he can see the vin, title, and the IPC and what it does.
In my own view, in the interest of eas of diagnostics combined with the most recent advancements in a specific model type, 1995 was a peak year. I consider myself lucky to own two '95 Seville's. There is no car I know of that is easier to do diagnostics on.
Mark D.

07-13-12, 08:02 PM
I got a 94 seville and do have some problems whit my solenoids it gives me a code sayin P117. i did hear from somewere that i should be able to overide/bypass the troublecode so that the car can continue to use all gears and not just the first gear. How a i able to do that. i do find the overide option in the menues but i do not understand all the numbers and parameter inputs.
How do i manage to overide P117 ?

07-13-12, 09:19 PM

Override is just for testing. It is not permanent.

Always post the code definitions along with the codes. No one has them memorized. I suspect that may be a shift solenoid? It will have to be replaced.

07-14-12, 01:48 PM
This is the code that is bugging me

P117 (E117) .................... Open/Short Solenoids/Solenoid Wiring (Transmission)

The previous owner of the car did make a complete renovation of the transmisson and by then he did also measure the solenoids and they were in perfect condition about a year ago.

07-14-12, 10:06 PM
I'd go into the overrides and test the solenoids. Maybe they've since failed or there is a wiring problem or something was installed wrong.

07-16-12, 03:14 PM
how do i test the solenoids in overide mode then?

07-16-12, 08:53 PM
:noidea: You'll need a FSM for that procedure or someone who has one will have to chime in with it.

07-17-12, 12:56 PM
I have the FSM for my car except I have no idea how to find anything in it. Three huge books and I'm clueless haha.