GM (Chevy Colorado '05) Passlock

jerry_njAugust 10, 2009

I finally figured out what is going on with my low mileage 2005 Chevy Colorado pickup. It is a very basic model, manual everything, including door locks and window cranks. Still it has a "security" system called Passlock. This somehow gets signals from the mechanical door lock and key operation (it seems) but I can not see any wires running form the door to the body and only one button, for the dome light, that signals the position of the door. So I wonder.

Problem, increasingly I get a red icon (padlock and car) which indicates the Passlock has been violated. The immediate problem is the starter will not function normally. When I turn the key to start nothing happens, but when I release the key the starter cranks, and thankfully disengages when the engine starts. To this I say "so what - spend $350 at the dealer's shop to fix? -ell no". Then things get worse. Now when the Icon is lighted and I turn the key and release it nothing happens, but on the second try (this is repeatable) the starter cranks when the key is released. It worked this way for several start/stop cycles. But now the engine will not continue to run, seems the ignition is shut off somehow by the Passlock when the starter is disengaged.

Looking on the web I see there is a whole business out there selling ways to defeat the GM Passlock, I am not ALONE!

Any advice on how to work around the GM Passlock without buying the "magic tool"... seems to be available for under $40, but I don't know if it really works, so testimony on how the defeat tool works would also be helpful.

This 2005 Chevy was the first USA manufactured car I have purchased in 25 years, the last was a 1980 Pontiac Sunbird (and those of you old enough to remember that car know why I went to Japan for my next car). Well, given I have only 10,000 miles on the Colorado, but its warranty is expired on time basis, and this is the third problem needing dealer attention, it may be another 25 years before I buy another USA car... not that I expect to live that long.

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Quote "this is the third problem needing dealer attention"

GM Passlock is a very simple, but effective system. The idea of it is to protect your vehicle from being stolen. Any shop that has recognized the need for their techs to be properly trained and equipped has purchased the factory scan tool (GM Tech II) and can handle this repair.

I have no experience attempting to bypass or work around this system and I never will because any time that I have spent with it has been focused on repairing it correctly.

    Bookmark   August 10, 2009 at 8:07PM
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Thanks, following my post a did a search on the web and it seems there's a whole industry built around dealing with the GM Passlock system, much focused on how to install a remote starter.

One site gives wiring diagrams and for three version of the Passlock starting with the system installed in the late 80s. Looks like a simple "snip a wire" if one wants to totally disable the system. For my "money" that's fine, I have a very basic model, standard and manual everything, steel wheels, nothing to attract attention..not a target for theft.

    Bookmark   August 10, 2009 at 10:33PM
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I searched and read a few as well after you mentioned them. A lot of the ones I read are from people confusing Passlock, and Passkey.

    Bookmark   August 10, 2009 at 11:34PM
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Thanks again john_g, and I enjoyed reading an old post of yours on the same subject, concerning a S-10, the model replaced by the Colorado.

In any case, careful reading of the owner's manual (I usually read for speed rather than content and miss all the important stuff).

From what I read I see the Passlock intervention is limited to the fuel system, disables the fuel injector(s) if there is an attempt to start the vehicle without a "proper" key in the ignition tumbler. So, why the symptom no starter crank untell the release of the key? Also, it seems the latest symptom of cranking but the engine dies as soon as the starter releases is consistent with the fuel being cut off.

Looks most like a tumbler problem, i.e., a legitimate key is not recognized/registered by the tumbler (or associated electronics - I also tried a back-up key with the same result). It seems possible too that a defective tumbler could intermittently not make the contact to engage the starter until the key is released - the fact that the starter then disengages when the engine starts is a still a mystery.

Guess I'll have to take it to the expert, and the Dealer seems to charge $150 and hour, so the price will be in the hundreds. Not a feel-good for Chevy in my book. My last previous Chevy was a 1969. Maybe I'll wait another 40 years before I buy another... oh, yes, I and perhaps GM will not be around in 40 years.

    Bookmark   August 11, 2009 at 10:27AM
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do a google search for other(GMC Colorado) truck forums, I'm sure there are piles of them out there, and I bet others are facing the same problem, and you can get a better idea on the fix, and the cost of it.

    Bookmark   August 14, 2009 at 9:24AM
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I took the Chevy to the dealer service, and expressed my belief that while the truck is 4 years old, with only 10,8xx miles on it any failure of the Passlock/Ignition has to be due to a defective product out of the factory.

As it worked out I could start the truck in the morning before it heated by the sun/weather. So I drove it in Tuesday morning and left it for whenever they could work on it. I got a telephone call tonight saying the truck was ready to pick up and I asked about the charges, it came to $160-something, not bad, and I was told it was an ignition (lock?) problem/replacement. It looks like I was given a "break" on the repair cost. I plan to talk briefly with the service manager to learn a little more anything that was covered by GM, as well as a better understanding on how the ignition works, it must have some electronics in it too, but as I suspected it seems the mechanics (physical) of the ignition lock was not able to recognize the key as legitimate and activated the Passlock, cutting fuel off to the injectors.

    Bookmark   August 19, 2009 at 9:59PM
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The problem is not repairable because the car was DESIGNED
to fail. This is the way cars are now being sold to we the consumer.They are DESIGNED to be Throw away as in Bic Razor or lighter. They are not cars but,,a throw away computer with EXTREMELY expensive parts and labor so that you will toss it away after a few thousand miles and buy another because you can not repair it.

    Bookmark   February 5, 2011 at 3:07PM
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I to own a 2005 chevy colorado with all the same issues.The car would not start maybe once a week sometimes more. I was told about this problem before i purchased this car (at a very reasonable price I might add)I was also told all the same nonsense about waiting fifteen minutes and trying again its nonsense because its at least 20 minutes for mine. I do believe I have comeup with a solution to this problem. When you exit the car instead of flipping the lock switch on the door get out and lock the door with the key therefore enabaling this faulty system. Ever since i began doing this 3 months ago iv only had the car not start once and that is probabally because I didnt lock the car with the key and just flipped the switch. Its a tough habit to break but a cheapo car owner will try anything right.

    Bookmark   February 7, 2012 at 9:06PM
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Surprised to see this post resurface in February 2012. So, I took a look.

Follow up on mine, it was a defective mechanical ignition key set (LOCK) best I can remember. I did complain to the GM district manager that such a failure had to be defective part was installed, and it shouldn't escape under the 36 months limit, they agreed to pay 50%, which I took.

My concern is the soft valve problem, which has a 7 year extension. My 7 year point is hit in June and no failure yet, but still under 20,000 miles on the truck. This failure if out of warranty will be costly, I'd guess $2K or so. The 7 year warranty on this item is limited to 100,000 mile best I can remember and is transferable. It applies to some newer years too, don't know which. But, if you have a valve failure be sure to check on warranty even if you purchased the truck second-hand.

    Bookmark   February 14, 2012 at 12:01PM
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Depends on the problem. Always check with a dealer first.

My '79 Toyota PU had a cracked Xost manifold. In '88 when I went to buy a new one at a foreign parts place they said check with a dealer cause they were required to cover some stuff for 10 years. I did. They did. Only hooker was they had to install it.

Now Jerry, get this! After retrieving my heap I re-torqued the nuts with a torque wrench (they were way off) and it hasn't cracked again or came loose either.

    Bookmark   February 16, 2012 at 11:22AM
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