Passlock problems? Anyone know of an easy fix or work-around?

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by HiLineMan, Nov 16, 2007.

  1. HiLineMan

    HiLineMan New Member

    99 Suburban 1500. Passlock system intermittently causes the burb to not start - perhaps you've seen my post in the "member intro" area - " New from Texas - Haunted 99 Suburban" ??? I am hoping someone here might know of a work-around. We have yet to ID something that causes the passlock system to think it is being stolen, and cuts off the fuel flow. The only work-around that seems to work every time is to wait one full hour and then try, and it always starts. But waiting one hour is not very practical 99% of the time. I read someplace that when it malfunctions, you turn the key to the "on" position, and wait a few minutes, till the "security" light on the dash goes out, then it should start. But, wouldn't you know it, I can't get it to malfunction, so I can't test that work-around. Anyone have any ideas? Thanks.
  2. HiLineMan

    HiLineMan New Member

    So .... I guess no one else has this problem? Or is it that everyone else has just fixed it and didn't need a "work-around? It's been 2 weeks, and I still can't get it to malfunction. Other factors have prevented being able to take it in to a dealer. Oh well....
  3. 84fiero123

    84fiero123 Epic Member 5+ Years 1000 Posts Platinum Contributor

    There is a way to disable the system, but for the life of me I can’t remember how to do it.

    I would check with a dealer near you to see if it may be just a dirty or malfunctioning key. I don’t know about your year but the older ones had a resistor in the key. Very expensive to get copies made as I remember.

    I have to hunt down some other things tonight so I will look for what I can find about this.
  4. 84fiero123

    84fiero123 Epic Member 5+ Years 1000 Posts Platinum Contributor


    Gives the system parameters.

    You can check the system with a scanner.

    If I remember right, and I could be wrong you have to find out what the resistor value is in your key and substitute that same value resistor in the ignition circuit. But I am still looking for better info.

    Aha here we go.


    Warning, Will Robinson
    Very complicated.
  5. HiLineMan

    HiLineMan New Member

    Thanks. I'll read those two items and see what I can work out. I'm still hoping for something definitive in the way of a work-around. My experience with intermittant vehicle problems is that untill they cease to be intermittant (or malfunction ALL the time), they are very difficult to diagnose. Earlier this week I met a guy who directed me to a shop here in Houston, that speciallizes in steering column problems. He claimed they had lots of experience with GM's systems, and were very good at diagnosing problems. I'll give them a call soon, and see where that leads. Thanks again.
  6. jsbaker

    jsbaker New Member

    Do you have the keys with the visible contacts on the blades? Sorry I don't know how else to describe them. I don't know a whole lot about the passlock system but I had the same problem in my 97 malibu i used to have and I have heard of others having the same issues with other GM vehicles from around the same years.

    Malibue would do the same thing. Put the key in and all of a sudden the theft light is on. Had to wait 30 minutes to an hour most times, sometimes only 15 minutes. Not a good thing when you are a service tech who drives 500 - 700 miles a week around the city of Houston. Last things I read about them ended up being bad ignition lock cylinders.

    I also had a friend that was having the same kind of problem with her Isuzu Axiom and it ended up being dirty keys.
  7. HiLineMan

    HiLineMan New Member

    No, but I know what you are talking about, my folks gave us their '92 Buick and it's ignition key has a small black rounded rectangle, with an exposed wire in the blade, about midway between the tip of the key and the head. The '99 burb has no such chip, just a smooth blade with a blck rubber head.
  8. gmcjimmy88

    gmcjimmy88 New Member

    I had a similar problem in a 99 venture. I had a set of keys made at a local key shop (not GM) and the keys worked great for a few days then started locking the systems. Service guys at GM told me I could use the factory key and it would reset the system. So my thought is try a different key. If I recall my keys were not too much for replacements. But I might be thinking of a different vehicle. Either way Good Luck!
  9. HiLineMan

    HiLineMan New Member

    We inherited the burb when my DW's parents passed away (fall 1999 the burb was 6 mos old). The three keys we got all looked identical and all had black rubber heads - so we suspect that all are "factory" keys (but don't know for sure). I had a key made at the hardware store - plain steel, no rubber head. This plain key worked fine for me for 6 years, though I drove the burb infrequently, my DW drove it every day. When we started having problems with the burb, we suspected my plain key, so we stopped using it. Over time we we eventually stopped using two of the other keys and only used my DW's key. Very long story shortened the problems are so intermittant that we don't know anything, key-wise, for sure. Right now, it has worked fine for a month, DW has driven it with her key, I've driven it many times using my key - I can't get it to malfunction. Thanks for the input.
  10. 03envoy

    03envoy New Member

    This is true. Turn the key to the start position & wait 10 minutes. If you don't have kids making noise anyway, turn the radio off & listen. You can actually hear the thing unlock.

    Anyone out there know what to cut to by pass the PassLock system completely??? I guess this is a common issue. :happy:

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