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Chevy Tahoe



  • zzackzzack Posts: 8
    Your link to Fereral Register doesn't work. Can you summerize? Is a valid GM key required for extended use or is it as dave5319 said "there is no chip is these keys"?


  • zzackzzack Posts: 8
    I think I may agree with you that the Passlock Key is nothing special because I have also used a cheap key for a couple days and no problems. I did, to be on the safe side, keep a valid GM key wrapped in tin foil in the back seat just in case.
    However, I'm too chicken to use a cheap key without a definate answer as to how Passlock works and why the owners manual and the dealer both say that a valid (?) key is required.


  • zzackzzack Posts: 8
    You said, "The nice nurse looking..." My question is she also nice looking? Hey, by the time you get your 2002 all of the problems will have been worked out, or at least all the questions will have answers. My 2001 Yukon, which came off the line the middle of November, does not have any of the little problems (so far) that others on this forum have had. We love it!


  • Don't worry about using the "cheap" key there is no difference. Everything is in the ignition switch. I found the paper that explains this, the link is:
    There it will show you all the different types of passlocks.
  • kreykrey Posts: 41
    Has anyone tried to have the rear seat in a new Tahoe/Yukon remounted towards the back to gain a little leg room? Another 2-3 inches would be VERY nice.
  • don434don434 Posts: 43
    I`ll admit I`m a senior citizen and haul several senior friends. My chief design complaint with every chevy suburban since my very first - about 36 years ago - has been that it`s very hard for seniors to sit on the corner of the second seat and swing your feet around to clear the door post.
    There is not enough leg room to enter easily. I hope some one responds positively but I don`t think it can be done without a interior redesign. The floor suddenly is elevated just at the point you need to slide the seat to the rear. My mom is 96 years old and only about 5 feet - 2 inches tall. With her short legs she still has trouble getting in the rear. My wife reluctantly gives up her front seat whenever my mom rides with us.
    Are you listening GM!
    My sister in law also complains it`s hard to get in and she is only 46 so it`s not only an old fogey problem.

    As far as the physical characteristic of my part time nurse is concerned - I won`t comment except to say that: If my wife happens to be next door when the nurse arrives - she always returns home relatively quickly. :) :)
  • don434don434 Posts: 43
    GM has effectively driven me nuts trying to come up with a simple clear cut explanation. This section of the manual covers pages 8-841 through 8-882.
    Within two pages of the start of the section is a warning that under certain conditions an open in the pass-lock sensor system may NOT set a diagnostic trouble code ( DTC ). A scan tool is the auto mechanics major tool to locate troubles. Without DTC`s being set it`s hard to diagnose.

    On page 8-851 step 9 talks about RE-PROGRAMMING the SEED and the KEY.This is needed after you charge parts in this circuit.

    On page 8-880 advises that: The system is similar in concept to the passkey system.However the pass-lock system eliminates the need for a KEY MOUNTED RESISTOR.
    This system blocks the operation of the fuel injectors if the correct key is not used.

    All of this junk is fine but HOW IS IT that many have used a standard key - cut at many different key shops - and the truck has started and runs fine. If it was only one or two cases I might feel better. Makes you wonder just how efficient is GM`s Theft protection.

    Again the Service Manual advises one thing - practical experience dictates another. Did the original design intent cost to much or wasn`t easy to keep working - who knows.

    The service manual tells me outside GM keys don`t work - our friends say they certainly do.??????
  • ryanbabryanbab Posts: 7,240
    4.10 rear end is better for towing

  • cwaynecwayne Posts: 81

  • zzackzzack Posts: 8
    Thanks for your replys.

    Don't know who International Electronics is but if what they say (see below) is true I fail to see any value in the system and why hasn't GM changed their Documentation or informed their Dealers? It's not that they haven't had time.

    Dave5319 I agree that a "cheap" key seems to work so I guess this is another little mystery of life.

    "Introduced in 1996, GM has changed the VATS anti theft system to Pass-Lock system. This is a similar device to the VATS system, in that there is a resistor present during the start cycle. However, in the PASSLOCK system, the resistor has been placed inside the ignition switch, instead of the key."
  • Has anyone installed a rear dust guard - I think that is what they are called...

    We live in Boston and the rear window gets really dirty with the road spray. I assume that the rear air deflector would partially solve this problem.

    Has anyone had luck with them - do they work?

  • I was first on the scene of a car burning in the heart of DC and pushed the emergency onstar button. The radio cut off but nothing happened. Help came later so I took off and called them when I got home. They said I should disconnect the battery to reset and/or get it serviced (great). Then the DC police call me asking if I got carjacked and that Onstar couldn't locate my tahoe (the guy I called didn't know this happened). In the morning, I pushed it and it connected to the phone call feature--then later a guy comes from nowhere and says "sir are you there?" So he says it works fine. It's comforting that it doesn't work when I need it.......
  • The document I tried to refer you to was a petition for exemption from a federal parts marking standard, based on the effectiveness of Passlock. To get to the document try going to , then search on 'GM Passlock'. Choose the document titled "Petition for exemption...'.

    Here's an excerpt: 'Passlock...features an electronically-
    coded lock cylinder rather than an electrically-coded ignition key.
    Specifically, when the sensor detects proper lock rotation, it sends a
    code to the body function controller. If the correct code is received,
    fuel is enabled. If an incorrect code is received, fuel will be
    disabled for a ten-minute lockout period during which any attempts to
    start the vehicle will be unsuccessful."
  • Don, I manage to lose hours without the aid of a shot:c). Thanks for the info on the mirror. It seems to be working fine again. If i mention to dealer which i will next time i go in to start a paper trail for after warranty replacement, I will get the old "unable to duplicate" routine. The +12 VDC on pin 3 in reverse is interesting. It must overide dimming in reverse. BTW, i don't have a manual. We all appreciate the research you do on our problems and the explanations you give that we can understand. Mike
  • After 6 months of waiting(a long story), the wife and I picked up our new 2001 Yukon 1SC, 4wd in September. We have been very satisfied with the vehicle and haven't had any of the problems that I have been reading about on this forum. Well, I guess my luck has run out, and we are now getting a low coolant warning on the message center. When we first got the warning, I checked the coolant level while the engine was still hot, and it did look low. I then carefully removed the cap from the reservoir, and the coolant level came up to the cold engine fill line. Several days later I checked the reservoir with a cold engine, and the fluid level was fine. Has anyone heard of, or had this problem yet? Anyone have any ideas?

    Thanks for any responses and for all of the other great information that is on this site.

  • I had the same problem a few months ago with my 2000 Yukon. My low coolant light would go on and off (from day to day) and my coolant was never low. Had the dealer take a look and they said it was a bad sensor, so they replaced it and I have not had trouble since then. My dealer (GMC dealer in Phoenix area) did mention that they had seen quite a few Yukons & XL's with this problem.
  • Thanks for the torque specs!

    Don434 - Hope your doing better after all that 'rest' :-)

  • 2001 YUKON. Does anyone know what actually happens when you push the round AUTO 4 wheel drive button. Does the front differential get engaged without the transfer case? I have noted that when you push in the AUTO 4 wheel mode, there is a very slight additional "gear" noise coming from the gear train even though there is no slippage on any wheel. I can understand additional gear type noise when slippage is detected and the 4wd is actually engaging but I am suprised to hear it when there is no slippage and the auto 4wd is not actually engaged.
    What is happening when that button is pushed?
  • I have the 2000 light gray leather interior which look smore like natural. I got the med gray cloth covers. They match the plastic door trim better than the seats, but I wanted something darker than the seats so they wouldn't show too much dirt.

    If you call Supreme they will gladly send you fabric samples and suggest a match for your year/color combo. The samples is the only way to really choose, the colors on the web site are way off.

  • What's happening is that the front end is locked in when you push the button but there is no power transfer until wheel slippage is felt by the system. That's why you will hear additional 'gear' noise.

    This explained better in the owner's manual I believe.

  • ryanbabryanbab Posts: 7,240
    SUB you have been a huge help

  • I just learned that my "check engine" light is the result of a vacuum leak in the gas tank. They'll have to replace it. It's on national back order. Ack. I'm glad I made them put me in a rental. While they're at it, maybe they can put in a large one. :)

    Obviously they can't check the steering clunk without a gas tank attached.

  • ryanbabryanbab Posts: 7,240
    Truck trend Feb 2001 issue (got it today) compares the tahoe with the expedition and sequoia. Well theres a new option the Z71 is back. On the lift gate instead of a tahoe emblam there is a Z71 on the drivers side (kinda looks like the 99 silverados Z71 sticker not the new one that says offroad but its not a sticker its an emblam)

    Looks like this

    Z71 Chevrolet

    Price as tested with options (dont know what they do not list) was $38,287 including destination

    Base Price was $27,845
    Options $9742

    It was cheaper than the expedition and sequioa both of them were at $40K plus

  • I don't agree with the system that is used, Basically what there saying is that if someone gets a key that fits and turns then there in business(slim chance). If someone tries to use a knife or a screw driver than the fuel will be disabled. I think the chip in the key is a better design, no other key will work with out the chip.I have that on my 97 lumina and put a small piece of tape on the chip, the car would not start at all.

    As for the rear window getting wet or dusty, I install a Lund windjammer. I did notice a difference, the window does stay cleaner and dryer. The faster you go the better cause more air is forced down over the window. If I had to guess I think it helped about 50%. I don't think any of them will give you 100%.
  • The correct Mobil 1 oil filter for the 5.3 L is the M1-206.
  • don434don434 Posts: 43
    Several of the circuits in our GM vehicles are simply two component, series connected, voltage monitoring sensors. I would like to produce a three or five step alarm verification chart:

    Is the low coolant alarm not functional due to loss of ground to the sensors switch?
    Is the permanent low coolant alarm due to a stuck sensor/switch?
    Is a non-functional low coolant alarm due to loss of a 5 volt feed on the Light Green wire.

    Would one of our technicians be willing to reach under the edge of the surge/ coolant tank and unplug the connector. This should not turn on the low coolant alarm -please stop here and advise me if the alarm - low coolant comes on. Naturally the engine must be on at this time. The connector we are interested in contains two wires - one black and one light green wire.
    A voltmeter with the black meter lead going to the connector with the black wire and the red meter lead going to the connector with the light green wire should read +5 volts.

    The service manual shows the switch inside the surge coolant container to be a normally open connection. Pressure of the fluid at a low level will allow the switch to put ground on the light green wire dropping its voltage level to 0 volts and this sense lead should turn on the low coolant alarm message.
    The wiring diagram for this circuit is shown on page 6-579. If after looking at this circuit I think you will agree that you can safely short the electrical connector that you have disconnected. This should force on the warning message. By doing this we have proven out the ground wire is good and the +5 volt supply is functional plus the chips which turns on the alarm.
    If no one wishes to try this I understand for it`s your beautiful truck not mine.
  • don434don434 Posts: 43
    Since your dealer said that he has several other failures of the sensor, this may be a trouble that many may look forward to. According to the service manual the sensor itself can`t be replaced - they must replace the entire coolant surge tank. Would you mind checking your repair order and advise if they refer to the part replaced as a surge tank and in any case give us the part number. This info may help others. Please supply a little more detail of your vehicle such as 1/2 ton Suburban or Tahoe or Yukon and engine size.
    On post 146 I think you said that the coolant level rose when you removed the coolant tank cap. I may have misunderstood you and you really removed or loosened the radiator cap. This second action makes sense since the drop in pressure would cause a surge of coolant to be expelled.
    If I can obtain my requested tests I`ll produce a simple test or two to prove sensor or wiring troubles. If it would be of interest I`ll try to produce several diagnostic procedures. Maybe at a slow one every week or ten days.
    BTW the note about tank replacement for sensor repair appears on page 6-628. We don`t need a scan tool for these basic circuits - these things are a little part of dumbing down America. On many troubles they are a necessity but certainly not all. A volt/ohm meter is often enough.
  • There is no radiator cap on these vehicles. The surge tank has a 15 psi pressure cap, so removing the cap can cause the coolant level to rise. The owner's manual advises: "Never turn the surge tank pressure cap -- even a little -- when the engine and radiator are hot".

  • I noticed that when I plug my cell phone adaptor into the lighter my FM reception becomes alot worse then when it is fringe areas. Has anyone else noticed this?

  • I purchased some PIAA 520 driving lights for my 01 XL and planned on hooking them up using the high beam wire as my switch so they would dim with the high beam. I asked PIAA customer service before I purchased them and they said this would work. After I got them in I was talking to a tech support guy and he said that the 00 & 01 Yukons, Subs & Hoes have a "Switching Ground System" and thier is always current running through the high beam wire even when they are off and this method of installation will not work. He said I would have to dim the 520's seperate from the high beam with their switch whenever I meet another car.

    Told him this was crap and was going to return them and he said they have an old wiring harness that has an extra ground that would allow me to do what I want. I expect to receive this harness within the next few days and will report back if it works.

    Anyone out their hook up some driving lights and try to tie them into the high beam? Would like to hear your story.

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