Pass-lock

Tiny
ADAM GRAYSON
  • MEMBER
  • 2000 GMC SONOMA
  • 2.2L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 213,000 MILES
I recently purchased this truck. About a week after getting the truck, my starter went bad. I replaced the starter and a few days go by and then my ignition lock cylinder quits working. I removed the lock cylinder and purchased another one. When I went to go install the new tumbler, the security light starting flashing. Now it will only start and then immediately shut off, and my battery seems to be draining somehow. I have unhooked it until I can find a way to fix this pass-lock problem. I have looked online on how to bypass, how to reset, basically anything and everything to try and disengage or even fix the problem. Would rather not take it to a shop being I do not have an arm and a leg to pay for it. Any help or advice to solving this would be greatly appreciated. Thanks
Thursday, November 16th, 2017 AT 5:28 PM

20 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 34,206 POSTS
It is amazing how effective these systems are at keeping owners out of their vehicles? Fortunately there is a relearn procedure you can do yourself. It is a good idea to have a small battery charger connected during this procedure.

Turn on the ignition, with the engine off.
Attempt to start the engine, then release the key to on, vehicle will not start.
Observe the security telltale, after approximately ten minutes the telltale will turn off.
Turn off the ignition, and wait five seconds.
Repeat steps one through four two more times for a total of three cycles/thirty minutes, the vehicle is now ready to relearn the Pass-lock(TM) Sensor Data Code and/or passwords on the next ignition switch transition from off to crank.
Start the engine. The vehicle has now learned the Passlock(TM) Sensor Data Code and/or password.

Important: The vehicle learns the Pass-lock(TM) Sensor Data Code and/or password on the next ignition switch transition from off to crank. You must turn the ignition off before attempting to start the vehicle.
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Thursday, November 16th, 2017 AT 6:01 PM
Tiny
ADAM GRAYSON
  • MEMBER
  • 12 POSTS
I tried that already, it did not work. Is there another way by chance?
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Thursday, November 16th, 2017 AT 8:30 PM
Tiny
ADAM GRAYSON
  • MEMBER
  • 12 POSTS
It had what appears to be an aftermarket alarm on it, would that have thrown the security on. I removed the module for the alarm.
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Thursday, November 16th, 2017 AT 8:39 PM
Tiny
STEVE W.
  • MECHANIC
  • 14,759 POSTS
Aftermarket stuff can cause a lot of issues depending on how it was installed. It is possible they cut into the wiring for the pass-lock system and now the signal to the PCM is missing. You say you removed the module, did you find cut wires or scotchlock connectors on wires? I would verify that all the wiring is correct. If you have access to a dealer level scan tool you can watch how the security system responds to the key and what is going wrong.
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Thursday, November 16th, 2017 AT 10:14 PM
Tiny
ADAM GRAYSON
  • MEMBER
  • 12 POSTS
There was wiring that was cut, I followed all the wires, none connect to the passlock wiring nor do they go into the BCM. I was wondering if I can somehow delete the whole passlock system all together. Is there a way I can remove it and just have my computer flashed?
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Friday, November 17th, 2017 AT 1:24 AM
Tiny
STEVE W.
  • MECHANIC
  • 14,759 POSTS
Passlock on a 2000 does not talk directly to the BCM. It goes through the instrument cluster first. The cluster validates the signal from the sensor and tells the BCM to allow the engine to run. If that module was also remote start it probably tapped into that part of the system to allow the engine to run.

Because of the way pass-lock works it is hard to eliminate, the earlier systems were easy.

It sounds like there was something else involved with the system as well if you are having battery drain as well.

From your description I would recheck the wiring and make sure there is not some bypass box hidden away that is causing the problem, common place to put it would be behind the IP.
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Friday, November 17th, 2017 AT 8:31 AM
Tiny
ADAM GRAYSON
  • MEMBER
  • 12 POSTS
I went ahead and removed the wires from the module that was the aftermarket alarm. None of the wires were cut, they were just spliced into. All wires are good and not burnt. Is it possible that maybe my ignition switch could be bad? Could I use another pass-lock sensor/lock cylinder from another s10/Sonoma of the same year? And if possible is there a way to bypass or even disengage the pass-lock once the truck stays running?
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Friday, November 17th, 2017 AT 8:18 PM
Tiny
STEVE W.
  • MECHANIC
  • 14,759 POSTS
What were the splices made with? Burnt is not the issue with a splice, corrosion is.
Your truck is showing the correct symptoms of the wrong pass-lock signals. The catch is finding where. With a factory scan tool it is easy as it will show where the issue is as the key activates the sensor and the system responds. You might be better off getting it to a shop and have them scan it as replacing the parts is just going to put you right back at this point. It is possible the problem is not the switch or the sensor.
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Saturday, November 18th, 2017 AT 2:14 PM
Tiny
ADAM GRAYSON
  • MEMBER
  • 12 POSTS
I would not necessarily say spliced. More like a crimp connection. I have gone through the wires and all are good and tight. No corrosion and/or anything of that nature. I am just stumped. I am going to put it all back together and try the relearn process with the module out, to see if that works.
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Saturday, November 18th, 2017 AT 2:39 PM
Tiny
STEVE W.
  • MECHANIC
  • 14,759 POSTS
Just be sure to go through it three times, the cars are smart, they usually learn it in one pass, the trucks need all three.
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Saturday, November 18th, 2017 AT 3:18 PM
Tiny
ADAM GRAYSON
  • MEMBER
  • 12 POSTS
I will and I will let you know the outcome of it.
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Saturday, November 18th, 2017 AT 4:20 PM
Tiny
ADAM GRAYSON
  • MEMBER
  • 12 POSTS
I ended up up figuring it out. My passlock sensor was bad. I replaced the enitre piece on the steering wheel, did a reset, truck fired up with no problem and stayed running. Thanks for everything. Hopefully nothing else goes wrong.
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Wednesday, November 22nd, 2017 AT 6:12 AM
Tiny
STEVE W.
  • MECHANIC
  • 14,759 POSTS
Yeah it happens a lot, Glad to hear you got it fixed. Do you still have the issue of the battery drain or is it gone now as well?
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Wednesday, November 22nd, 2017 AT 12:13 PM
Tiny
ADAM GRAYSON
  • MEMBER
  • 12 POSTS
Yes, I had left it hooked up over night and came out the next morning to it only having around 8-9 volts. Threw it on a charger for about ten minutes, it fired right up. Been driving the truck to see if maybe it will hold a charge. Only other problem I'm having is with the ignition key tumbler. Sometimes it will turn with no problem other times I have to play with it and bit. Could I have installed it wrong? I've taken it off multiple times and reinstalled it only for it to do the same thing over again. Also, my steering wheel feels losing fitting, as it can move up and down while driving. I did delete the airbag, could that have caused the play in the steering wheel? Up&down anyway.
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Wednesday, November 22nd, 2017 AT 3:39 PM
Tiny
ADAM GRAYSON
  • MEMBER
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One more thing, my security light flashes after I shit the engine off. Even though I haven't set the alarm. Do I need to do another reset. I originally didn't do one with this lock cylinder, I just installed and it fired right up. Do I run the risk of my passlock engaging again for that reason.
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Wednesday, November 22nd, 2017 AT 3:49 PM
Tiny
STEVE W.
  • MECHANIC
  • 14,759 POSTS
Is it a new cylinder? Or a used one? It sounds like it's in need of some graphite lube to make it free up. It's possible it's related to the column motion as well as it could be binding in the steering lock. What parts move? The wheel only or is this a tilt wheel? The tilt columns get loose inside, LOTs of videos on that.

Does the light flash constantly or does it flash for a minute or so and stop? There are a couple options with the passlock system. One just disables the starter, the other option also covers contents. That option usually flashes the security light as a warning.
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Wednesday, November 22nd, 2017 AT 7:14 PM
Tiny
ADAM GRAYSON
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  • 12 POSTS
I got the truck running finally, my initial lock cyclinder was defective, order a new one, installed and fired right up. Now just the yesterday, I was driving and my wires for the passlock that is next to the ignition arked and sent Sparks flying. I was just driving down the road when this happen. My security light stays on constantly while driving and only flashes when I shut off the truck. Now in the ignition switch itself, the red/white wire is the one the arked, followed by the three wires that plug into the passlock sensor. It still starts and drives, but feels hesitant to shift. Shifts at higher rpm's than before.
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Saturday, November 25th, 2017 AT 12:49 AM
Tiny
STEVE W.
  • MECHANIC
  • 14,759 POSTS
Not a good thing, it sounds like the PCM may have been scrambled a bit. You could try the "Disconnect the battery for 10 minutes" routine and see if it recovers. BUT if the PCM was damaged all bets are off that it will start again.
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Saturday, November 25th, 2017 AT 5:05 PM
Tiny
ADAM GRAYSON
  • MEMBER
  • 12 POSTS
The truck runs and drives. Starts with no problem, minus the lock part on the ignition. Feels like it doesn't want to turn. It does eventually, bit that's after I wiggle it in every way possible for about 5 minutes. All fuses and relays are good. All other wiring is good. No corrosion or burnt wires.
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Saturday, November 25th, 2017 AT 10:30 PM
Tiny
STEVE W.
  • MECHANIC
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That is the new cylinder correct? Is it NEW or a used one?
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Tuesday, November 28th, 2017 AT 11:06 AM

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