Theft deterrent learn 97+ year vehicles

[matuva]

Does the security light comes on and stays on only or does it blink when you key on?

You might have a passlock issue.
Try the relearn 1st, if not the resistor trick gave very good results for me

View attachment 37583

 

[Turbine Doc]

I merged Als latest information with one I had posted @ another site long time ago:

If you have a 97+ year you may need to do this when swapping PCMs or installing a reflash PCM

Code that comes up would be DTC P1631 THEFT DETERRENT PASSWORD INCORRECT

Important: While the PCM is in the Auto Learn Procedure, battery voltage must be maintained at all times. This procedure must be followed exactly as indicated or the procedure will have to be repeated from the beginning.

The times posted are minimum time can go over the limit but not under it


1.. Attempt to start vehicle (vehicle will start and stall) (in my case never got start only crank)'"after the engine has stalled leave the ignition ON for 10 minutes (security light will remain on for 10 minutes and then go out).

2. After the Security lamp turns OFF, turn the ignition off 'for 30 seconds.

3. Again, attempt to start vehicle (vehicle will start and stall), (again crank no start for me C-N-S) after the engine has stalled leave the ignition on for 10 minutes (security light will remain on for 10 minutes and then go out).

4. After the security lamp turns OFF, turn the ignition off for 30 seconds.

5. Again, attempt to start vehicle (vehicle will start and stall) , (C-N-S); after engine has stalled leave the ignition on for 10 minutes (security light will remain on for 10 minutes and then go out) or until DTC P1631 sets.

6. Turn the ignition off for 30 seconds.

7. Turn the ignition on wait 30 seconds..

8. Attempt to start the engine.

Does the engine start and operate normally, IF NO: REPEAT # 1-8.

Conditions for clearing the DTC

. A History DTC will clear after forty consecutive "Warm - up cycles" which is a completed start with ECT getting > 170F; If no failures are reported by this or any other emission related failure.

. PCM battery voltage is interrupted. .

Or if you have a scan tool you can use the clear code function if Theft learn was successful and no other codes are present.

 

[toddlnrd]

Thanks guys. I will know more about the condition of my truck tomorrow (Monday). I have had to work Fri, Sat and Sun, so I could not go to the shop to talk to mech. and have him try your suggestions. He may have already tried, I don't know. I work tomorrow also, but my second job gives me much more flexibility to leave and/or call to check on the progress.

matuva - I am interested in the bypass, but only if it is a recurring problem.

Any recommendations if I have to get a new PCM?

Todd

 

[Merv]

Strange cutting out problem

Hi All

Brand new here, and a brand new owner of a 97 Suburban 6.5. I have a strange problem and I am wondering if it is related to the above. Picked up the truck today and it ran perfectly on the way home, over an hour's journey, stopped off here and there, shut off, restarted, no problems, ran like a top. I parked the truck at home, moved it a couple times, still no problems.
I then started to do some cleanup stuff, polishing and so on, left all 4 doors open to air the vehicle out and pottered around doing some polishing and buffing of the paint on the hood (that took over an hour). I then sat in the truck (still with the doors open) and started playing around with a little FM transmitter so as to play my iPod through the car stereo. After a while I then decided to start her up and idle for a while (to make sure the batteries were OK, and also just to hear the engine running ). It ran for about 30 seconds and then cut out. Hmm.., started up again and same symptoms. Started up again and went for a short drive, seemed to be OK and parked her again.
About an hour or so later, I needed to pop over to the store to pick up a couple things, that is when the fun started. THe engine cut out while driving, like the ignition had been turned off. I though maybe the fuiel gauge was wildly inaccurate (it was showing between 1/2 and 3/4). Managed to get to the gas station eventually (after numerous cut outs) and filled her up with some of the finest Arab Elixer. It took about 80 litres, so there was still plenty fuel.
Took a few attempots to get her running again and got home eventually.

Now, I am wondering if perhaps leaving the doors open and with the ignoition on may have triggered some kind of anti-theft thing (???). As I said earlier, it was running perfectly until before that. (PMD decided to give up the ghost????? Maybe??? I have no idea, but I am confident it is not fuel related, when it is running it runs beautifully, with loads of power)

Any help would be much appreciated

 

[NVW]

Welcome to TTS

Sounds like a PMD, only way I know how to check it is with a known good one.

Mods may want to put this into a new thread for Merv.

 

[ak diesel driver]

could also be ign switch

 

[great white]

Hi All

Brand new here, and a brand new owner of a 97 Suburban 6.5. I have a strange problem and I am wondering if it is related to the above. Picked up the truck today and it ran perfectly on the way home, over an hour's journey, stopped off here and there, shut off, restarted, no problems, ran like a top. I parked the truck at home, moved it a couple times, still no problems.
I then started to do some cleanup stuff, polishing and so on, left all 4 doors open to air the vehicle out and pottered around doing some polishing and buffing of the paint on the hood (that took over an hour). I then sat in the truck (still with the doors open) and started playing around with a little FM transmitter so as to play my iPod through the car stereo. After a while I then decided to start her up and idle for a while (to make sure the batteries were OK, and also just to hear the engine running ). It ran for about 30 seconds and then cut out. Hmm.., started up again and same symptoms. Started up again and went for a short drive, seemed to be OK and parked her again.
About an hour or so later, I needed to pop over to the store to pick up a couple things, that is when the fun started. THe engine cut out while driving, like the ignition had been turned off. I though maybe the fuiel gauge was wildly inaccurate (it was showing between 1/2 and 3/4). Managed to get to the gas station eventually (after numerous cut outs) and filled her up with some of the finest Arab Elixer. It took about 80 litres, so there was still plenty fuel.
Took a few attempots to get her running again and got home eventually.

Now, I am wondering if perhaps leaving the doors open and with the ignoition on may have triggered some kind of anti-theft thing (???). As I said earlier, it was running perfectly until before that. (PMD decided to give up the ghost????? Maybe??? I have no idea, but I am confident it is not fuel related, when it is running it runs beautifully, with loads of power)

Any help would be much appreciated

Pass lock doesn't work that way. In a nutshell, if you don't start the vehicle witha key (there is no transponder in the key, it's in the column) it will activate.

Leaving the doors open while running won't kick it in.

Pass lock is more of a pita for the owner than it is for a thief. If you jam a screwdriver in the ignition cylinder and turn it, pass lock will think everything is fine and happily let the sob drive away.

I program pass lock out on all the PCM's I do. It's a pointless system just waiting to bite you in the butt. It won't even slow a thief down (neither will those stupid door handles) but it will leave the average owner dead on the side of the road.

Your stalling issue lies elsewhere.

First off: do you have a scanner or reader that you can check the PCM for trouble codes?

Even a cheapy $10 elm327 unit off eBay will be able to at least read your trouble codes.

Whereabouts are you in Canada? If by some miracle you are close by, I can drop by and have a look.....

 

[Merv]

Hi there

First off, thanks for the replies, much appreciated. To Great White, I am in Ancaster, ON, just west of Hamilton.

Based on further reading late last night, it does sound like the PMD may be the culprit, it just really puszzles me that it was running just fine before I left it with the doors open and the ignition "On". Just co-incidence?? THis is all brand new territory for me (although I did own a '99 diesel Suburban previously, which I bought from the dealer as a demo when money was good, then had to sell 2 years later when the bottom fell out of the IT market )

 

[great white]

Hi there

First off, thanks for the replies, much appreciated. To Great White, I am in Ancaster, ON, just west of Hamilton.

Based on further reading late last night, it does sound like the PMD may be the culprit, it just really puszzles me that it was running just fine before I left it with the doors open and the ignition "On". Just co-incidence?? THis is all brand new territory for me (although I did own a '99 diesel Suburban previously, which I bought from the dealer as a demo when money was good, then had to sell 2 years later when the bottom fell out of the IT market )

Yeah, you're a couple days drive from where I am so no stopping in for a brewsky and a repair session on the weekend.

The stalling and the doors open thing is coincidence. Correlation does not equal causation.....

The PMD is a known weak point on electronic 6.5's. It can fail all at once, or it can fail in little "hiccups" until it just fails completely. There is no real rhyme or reason to it.

The unfortunate part of it is that unless there are very definitive trouble codes stored in the PCM for an unrelated fault, the only way to really troubleshoot a PMD is to replace it. There are a few trouble codes like excessive closure time in milliseconds that will indicate the PMD, but there are none specifically codes saying "PMD bad".

Now the really bad news: anywhere from 250-500 bucks for the module.

250 would be a straight up parts store replacement module to go back on the pump, 500 for a revised module (there are a couple redesigns from Stanadyne and aftermarket suppliers) and remote mount (PMD isolator is the term you'll usually hear).

If you go with an "isolator" (highly recommended if you want your PMD to live a long and happy life), get one that mounts it outside the engine bay. Usually behind the front bumper somewhere. Heat is the issue. PMD's run hot in just regular operation, you need to get it away from the engine heat so it has a large temp delta to shed heat.

I use a Heath Diesel PMD kit. It's been in there about 3 years now with no troubles (well, I had a corrosion issue, but that was more or less my own fault). It has a 7 year warranty on it which is about as good as you're going to get. I believe Leroy matches this warranty on his kit also.

Or, you could buy a "tested good" used one off ebay for somewhere around 50 bucks. Total crap shoot there and I wouldn't trust a used one for very long. It's a "get you through" measure.

That being said; I have a used one I bought off a member here that I keep in the glove box as a "just in case" spare. It's saved my bacon at least once....

 

[NVW]

http://www.leroydiesel.com/Page_2.html

Several options here

 

[BDH]

I merged Als latest information with one I had posted @ another site long time ago:

If you have a 97+ year you may need to do this when swapping PCMs or installing a reflash PCM

Code that comes up would be DTC P1631 THEFT DETERRENT PASSWORD INCORRECT

Important: While the PCM is in the Auto Learn Procedure, battery voltage must be maintained at all times. This procedure must be followed exactly as indicated or the procedure will have to be repeated from the beginning.

The times posted are minimum time can go over the limit but not under it


1.. Attempt to start vehicle (vehicle will start and stall) (in my case never got start only crank)'"after the engine has stalled leave the ignition ON for 10 minutes (security light will remain on for 10 minutes and then go out).

2. After the Security lamp turns OFF, turn the ignition off 'for 30 seconds.

3. Again, attempt to start vehicle (vehicle will start and stall), (again crank no start for me C-N-S) after the engine has stalled leave the ignition on for 10 minutes (security light will remain on for 10 minutes and then go out).

4. After the security lamp turns OFF, turn the ignition off for 30 seconds.

5. Again, attempt to start vehicle (vehicle will start and stall) , (C-N-S); after engine has stalled leave the ignition on for 10 minutes (security light will remain on for 10 minutes and then go out) or until DTC P1631 sets.

6. Turn the ignition off for 30 seconds.

7. Turn the ignition on wait 30 seconds..

8. Attempt to start the engine.

Does the engine start and operate normally, IF NO: REPEAT # 1-8.

Conditions for clearing the DTC

. A History DTC will clear after forty consecutive "Warm - up cycles" which is a completed start with ECT getting > 170F; If no failures are reported by this or any other emission related failure.

. PCM battery voltage is interrupted. .

Or if you have a scan tool you can use the clear code function if Theft learn was successful and no other codes are present.

I have a problem that seems to the same security light on starts than stalls I have cleaned and checked the ground connections, I tried the the relearn procedure twice but after the 10 min. wait with the key on the security light will not go out. any suggestions would be great
Thanks