Northstar Engines and System Technical Discussion Discussion, PCM Overrides? in Cadillac Engine Discussion; I've seen references in various places on the web and heard from other people with Northstars that when they go ...
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.
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.
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.
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.
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.
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.
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.