: No access to PCM info via dashboard OBD?



loweldo
04-30-08, 09:48 PM
Background:
My mother has a 1999 DeVille with a touch over 72k miles on it. I've been having a problem getting complete information regarding the OBD menu hierarchy and a listing of what abbreviations and numbers go with what sensors. I complied a good amount of info from literally hundreds of sources thinking when it was complete I could release it in one document on the forum for use as a reference. I'd really like to get my hands on something that tells me what the acceptable values are and the thresholds of each sensor so I could see what's good and what's bad (potentially use it as a preventative maintenance measure).

Problem:
I have a partial list of sensors from a 1996 internal release from GM and I wanted to try and match up items on the list with PCM DATA, INPUT, and OUTPUT sensor readings from her car. Here's the issue: I tried entering diagnostic mode with the engine off and key in acc position but the only two "PCM?" options I get are "PCM CODES?" and "PCM CLEAR CODES?". :hmm: A 59-page alternator repair guide that was an internal-only GM publication mentioned that the remainder of the PCM options might only be visible with the engine running at idle and the transaxle in park but when I tried that the results were unchanged. :annoyed: I get sensor data/inputs/outputs information from the IPC but I have no documentation to decipher what that means (that's my next project after the PCM documentation!).

Questions:
Anyone have any ideas where the missing menu items are?
Is it something with that particular model's setup that maybe it's only viewable by a computer hooked up to the diagnostic port? (I've yet to try that, my friend is borrowing her boyfriend's OBD-II computer he uses to work on his Porsche)
I have a 1988 Eldo and the diagnostic mode on that shows everything, is this a display difference between type I and type II?
Is there a different deciphering legend between the abbreviations used on DIC displays for OBD-I and OBD-II? or can I use the same master list for both?I'm starting to really get into this and I'm almost sorry I went IT major instead of auto-tech major! With the price of gas and two Cadillacs in the household I want both of them in peak shape.

Ranger
04-30-08, 10:52 PM
Is there a different deciphering legend between the abbreviations used on DIC displays for OBD-I and OBD-II? or can I use the same master list for both?
And there is your problem. OBDI would give you DATA and OVERRIDES, OBDII doesn't.

I'd really like to get my hands on something that tells me what the acceptable values are and the thresholds of each sensor so I could see what's good and what's bad (potentially use it as a preventative maintenance measure).

A FSM is what you want. Ebay is your friend.

loweldo
05-01-08, 01:36 AM
As far as the OBDII, I do get options for DATA?, INPUTS?, OUTPUTS?, and OVERRIDE? choices for IPC and one or two other options (I'd have to go back out to the car to look for which exact ones they are). I guess this means I have to hook it up to a computer to read them or do they not exist? I believe that somewhere my boyfriend has the GM Techline ESi DVD v2005.01 which is supposed to have information on her model so I'm going to borrow that this weekend.

Ranger
05-01-08, 05:22 PM
I could have sworn that OBDII didn't have access to that stuff.

trg2000
06-01-08, 11:37 AM
I have the same problem and urgently need to override...I can't find the pcm menu items either
and need this done asap so I can override tranny and
drive on the freeway...can't get out of 2nd gear!

Did you find an answer to those missing items in pcm menu?

Trent





Background:
My mother has a 1999 DeVille with a touch over 72k miles on it. I've been having a problem getting complete information regarding the OBD menu hierarchy and a listing of what abbreviations and numbers go with what sensors. I complied a good amount of info from literally hundreds of sources thinking when it was complete I could release it in one document on the forum for use as a reference. I'd really like to get my hands on something that tells me what the acceptable values are and the thresholds of each sensor so I could see what's good and what's bad (potentially use it as a preventative maintenance measure).

Problem:
Here's the issue: I tried entering diagnostic mode with the engine off and key in acc position but the only two "PCM?" options I get are "PCM CODES?" and "PCM CLEAR CODES?".

danbuc
06-02-08, 05:02 PM
Some OBDII models did, and some didn't. I believe the cutoff for that feature was around '98 or so. My '98 STS does not allow me to access any overides, or directly view sensor data via the cluster, just view/clear codes and change preferences in "feature programming". After OBDII was indtroduced, they stopped giving the common folks the ability to tinker.....sucks doesn't it!

Submariner409
06-03-08, 09:44 AM
............and, if you have entered the mode which asks "ALL CODES" and you answer "NO", then when you get the messages PCM? (answer yes), CLEAR PCM CODES? (answer no), then INFO to the next module and do the yes/no thing all over again.

If you initially answer NO to ALL CODES? you must then step through the modules manually. This gives you more time to write everything down, and you can go forwards or backwards using the INFO up/down rocker.

No, I can't get to the PCM brains through my DIC.

Tommy Deville
06-05-08, 09:07 AM
I could have sworn that OBDII didn't have access to that stuff.


I can on my 97'.

ManuCadillacStS98
05-10-09, 08:19 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

Submariner409
05-10-09, 09:42 AM
There is no way to enter the PCM from the DIC/buttons on the 98 STS. The DIC is used to read any DTC's and reset fault codes from individual modules. You cannot program the PCM. Only someone with a GM Tech-II can get in, and then you can't change individual maps.

You'll have to do a ton of homework in here and Seville to see what has been tried over the last 6 years. AJxtcman can alter some values, but he's always grooming his work, so there is currently NO PCM reflash on the street which will gain you much except to remove the top speed limiter, if any is set.

Down at the bottom of this Forum there is a thread entitled "PCM Tuning" - it's NOT for Northstar PCM's, but many jump the borders, so there IS N* info in there. But it's the same story - no OBD-II tuning answers.

I hate to say this, but so many people have asked this question so many times, and the answer is always the same, so you're :horse: