Newbie with a quick PassLock question

[Gundoc]

Longtime lurker here, who has learned a lot by lurking. Thank you all for that.
I have also posted in the Introduce Yourself location.

I have a ’99 4x4 Suburban with a 5.7. I was having PassLock issues that I believe were brought about by a bad battery. It seems to be working fine now, but I don’t trust it. It has occurred to me that the PassLock caused a Gold Die Hard to go bad in less than two years. Whatever the case, I don’t trust it, especially on a 25 year old vehicle.

Lurking here leads me to believe that the best fix is to delete PassLock from the ECM (or whatever the “main brain” is called.) My mechanic thinks he has the scanner to do it. He wants $120 if he can, nothing if he cannot. That sounds fair to me.

Finally, my question. Assuming my mechanic can delete the PassLock, would it be advisable to unplug the PassLock module that is located near the ashtray, behind the knee bolster? My thinking is the module could cause other issues even if the ECM is not asking it for a “go signal.”

Thanks in advance for any replies.
Gundoc

 

[DonYukon]

Have you had the system checked to verify if it was the Passlock that caused the Parasitic draw? But yes, If he can delete its need from the ECM you should be fine. Assuming he's disabled it correctly removing its ability to cut power to the fuel system ect... I dont think you will run into any other issues. he could test this by pinning out the module after its disabled to see if its still creating a draw on the system. without a diagram in front of me Unplugging the module shouldnt create further issues with anything else as the ECM wouldn't be requesting signal from it. my only concern without checking the wiring shcematics to verify that any other system doesnt require to travel through that system using it like a relay.

 

[Gundoc]

Have you had the system checked to verify if it was the Passlock that caused the Parasitic draw? But yes, If he can delete its need from the ECM you should be fine. Assuming he's disabled it correctly removing its ability to cut power to the fuel system ect... I dont think you will run into any other issues. he could test this by pinning out the module after its disabled to see if its still creating a draw on the system. without a diagram in front of me Unplugging the module shouldnt create further issues with anything else as the ECM wouldn't be requesting signal from it. my only concern without checking the wiring shcematics to verify that any other system doesnt require to travel through that system using it like a relay.

Thanks for the reply. I don't know if the battery went bad due to a parasitic draw, if so if it was the PassLock that did it, or if it was just a bad battery.

What I do know is that I was having PassLock issues: starts, runs a few seconds, SECURITY light staying on. I could usually get it to work by disconnecting the battery. Sometimes (perhaps every time?), when I reconnected the battery, I would have to leave the key on for 10-12 minutes until the SECURITY light went out. Usually, I had to leave the battery disconnected for more than a few minutes, but i never could determine the minimum amount of time (determining that is not an easy test.) Connecting a jumper across the battery connections (battery removed, of course), hoping to more rapidly drain any "memory", didn't seem to speed up the process. Finally, the battery went way down overnight when NOTHING was connected to it. That was certainly not normal. I had the battery tested and got it replaced under warranty.

When I connected the new battery, I went through the full 30 minute "relearn" procedure. I don't know if a single 10-12 minute key on would have done it or not. Once I decided on the full 30 minute relearn, I stuck with it. Everything seems fine now, but I still don't trust it. My gut tells me that the chance of the PassLock preventing a theft is less than the chance of it causing trouble down the road. It is likely not a high target truck, and my lifestyle now is such that I don't often put the truck in theft vulnerable situations. I'm willing to take the chance and spend $120 for piece of mind. Thus, my original question.

 

[AK49BWL]

Don't unplug the module, that same module also controls your variable power steering. If VATS is turned off in the PCM, the PCM won't care what that module says anymore.

 

[Gundoc]

Don't unplug the module, that same module also controls your variable power steering. If VATS is turned off in the PCM, the PCM won't care what that module says anymore.

Thank you for the reply! I admit than when I first read your post, I thought "No way the PassLock module has anything to do with the Variable Ratio Power Steering." I have a set of service manuals and I looked it up.

You are correct!

I learned something new today, which is is good unless I learn bad news. Thanks again!

 

[618 Syndicate]

A scanner cannot tune out VATS/Passlock. It can only be disabled via a tune. Find someone with HPTuners (depending on what area of TX you're in I'm sure some folks here will have suggestions) and have them do it. Alternatively, send your ECM to someone and have them do it for you. truck will be down a while with that method. A third option is to buy another (used) ECM and send that one off to be tuned, when you get it back it's a plug and play swap.

 

[DonYukon]

I know Black Bear Performance Tune can get rid of it

 

[Gundoc]

OK, forget that part about everything seems OK now. It is back to doing the "PassLock start and die", so it wasn't the bad battery. So I am definitely looking to get the function deleted in the ECM.
But what AK49BWL posted about the PassLock module also having to do with the Variable Ratio Power Steering (VRPS) got me to wondering. Does this same module sometimes cause issues with the VRPS, and how can you tell if it is?

 

[AK49BWL]

Most of the time the issue isn't with the module, but the little sender disc at the bottom of the steering column that gets dead spots in it, causing the system to provide full pressure at random and often inconvenient intervals. I gutted mine and replaced the solenoid and high pressure line from the PS pump with a non-variable setup that 96 trucks still had. Never looked back.

 

[df2x4]

X2 on deleting the EVO steering with '96 parts. I fought to keep the EVO functional in my '97s for way too long, replaced the column sensor in both multiple times. Finally gave up and bypassed the EVO, and I don't miss it one bit.

Regarding the PassLock delete... It would be an easy job for anyone with access to HPTuners, EFILive or JET DST tuning software. It's as simple as checking a box and applying the changes.