Passlock question

[evilunclegrimace]

Here goes, I bought a '98 Suburban and from what I understand it has the passlock system in it. I have not had any problems with it yet(knock on wood) I have read the threads about eliminating the system with resistors and or switches and I had a thought. Is it possible to find and install a PCM/Computer from an earlier year truck with the same options minus the passlock and have it behave correctly. I understand that I could send the Puter out and have it programmed out but don't want to spend extra cash right now.

 

[df2x4]

Here goes, I bought a '98 Suburban and from what I understand it has the passlock system in it. I have not had any problems with it yet(knock on wood) I have read the threads about eliminating the system with resistors and or switches and I had a thought. Is it possible to find and install a PCM/Computer from an earlier year truck with the same options minus the passlock and have it behave correctly. I understand that I could send the Puter out and have it programmed out but don't want to spend extra cash right now.

The PCMs switched from five connectors to four between '97 and '98, so you'd have to do some wiring at minimum. Sounds like a lot more trouble than it's worth IMO.

 

[evilunclegrimace]

The PCMs switched from five connectors to four between '97 and '98, so you'd have to do some wiring at minimum. Sounds like a lot more trouble than it's worth IMO.

well crap! I guess that shoots that idea down. I will have to figure something else out Thanks.

 

[GreenZ98]

You can either send blackbear performance your computer and they can cut it off with a tune. Or they can send you a new computer with it already tuned out, that's the route I took with my 98 when I had passlock issues.

 

[df2x4]

I think there are other mail order tuners who may do just a PassLock disable for cheaper than a full tune as well. Off the top of my head you may want to check with Nelson Performance, PCM4Less, or Westers. Black Bear Performance might do that as well, I've never asked them as my trucks are both '97s.

I have personal experience with Black Bear Performance and I would strongly recommend them.

Alternatively, if you have someone in your area who has HPTuners then they could disable PassLock for you. The '98+ black box PCMs are supported by HPTuners.

 

[evilunclegrimace]

I think there are other mail order tuners who may do just a PassLock disable for cheaper than a full tune as well. Off the top of my head you may want to check with Nelson Performance, PCM4Less, or Westers. Black Bear Performance might do that as well, I've never asked them as my trucks are both '97s.

I have personal experience with Black Bear Performance and I would strongly recommend them.

Alternatively, if you have someone in your area who has HPTuners then they could disable PassLock for you. The '98+ black box PCMs are supported by HPTuners.

Thanks for the info. I will look into it as I have a spare 'puter that could be modified.

 

[Ken K]

Do you had visible resistor chip in shank of key? Never saw this on a truck. Passkey is get pass the key, while passlock is getting pass the lock. A ring around ignition switch acts like magnetic field, then works as antenna. This causes the hidden RFID chip in the plastic head of key to produce a long code. If it matches, the passlock module sends a signal to the PCM. They varied from constant 5 volt to frequency on later models. This allows spark and injectors to work. Does the shank of your key have a + symbol stated on it?

You can go to LT1swap.com for $75 Brendan in MO. can program to remove VATs PCM input.

 

[evilunclegrimace]

Do you had visible resistor chip in shank of key? Never saw this on a truck. Passkey is get pas the key, while padlock is getting pass the lock. A ring around ignition switch acts like magnetic field, then works as antenna. This causes the hidden RFID chip in the plastic head of key to produce a long code. If it matches, the passlock module sends a signal to the PCM. They varied from constant 5 volt to frequency on later models. This allows spark and injectors to work. Does the shank of your key have a + symbol stated on it?

You can go to LT1swap.com for $75 Brendan in MO. can program to remove VATs PCM input.

I believe that you are referring to the VATS system that had the resistor in the key it self. Passlock has the resistor in the ignition switch and that system was introduced in the '98 model years on trucks.

 

[Ken K]

I hate he word "Auto" correct as it changes the words I type. But yes, GM had passkey 1 & 2, the passlock, Immobilizer, Passlock 3, Passlock 3+ which is + with circle on it. But in the late 90's, Passlock on trucks was the first design. The RFID is in the head of the plastic key and communicates with the ignition switch ring/anti-theft lock module. Early ones generated a 5 volt constant voltage input to PCM. Next gen produces a predetermined frequency many a 20hz. This too was constant freuentcy that once the PCM received, had and "Electronic-Hand-Shake" then defaulted to an new strategy. If the vehicle is started, everything works normal. If the signal is lost or class2 network goes down while running, the engine stays running while turning on the theft light. Only once per cycle? No. It ignores the Passkey system all together and allows the vehicle to be started. The exact system the 1998 Suburban has on it, will be found on paper service manual. The electronic version of "Service Information" copied only engine and transmission for 97, 98 only, then went full blown electronic with all systems, accessories, body, electrical and diagnostic flow charts going forward. Hanyes of Chiltons are useless for exact vehicle systems. Mitchells and All-Data paid to copy certain pages of GM service information, but not all pages. Using these system in a shop or garage will find "Holes" in service information.
It is the same issue for software for SnapOn and others when it comes to access on systems. Body function take a hit and only "One" fail-records instead of all five fail records. A tech can go back in time with these fail record to see the same code set and certain temps, speed, RPM, TPS, MAP etc. This becomes helpful as after a fix, these perameters can be reproduced to see if the code returns, also check if code is pending, waiting for second failure when the test is run...only on type "B" codes, "C" codes and now "D" codes. "A" code types set the MIL/CEL on as soon as the code sets. Vehicle malfunctions are different from MIL/CEL as they will turning on Service Vehicle Soon" lamp.
I this I had these paper service manuals but do not and limited information is on the internet. ASE Master since 1978.

 

[Tomcat58]

The PCMs switched from five connectors to four between '97 and '98, so you'd have to do some wiring at minimum. Sounds like a lot more trouble than it's worth IMO.

https://itstillruns.com/disable-ignition-security-gm-7621606.html