Top 10 2001 GMC Yukon XL Questions & Answers

replace the transfer case shift control switch . there is a TSB # 02-04-21-004 released in april of 2002 , on your unit , you may also find a code # B2725 set in the body control module , fualt explination - fualt in transfer case shift control switch . GM part # 15709327 , also he is an excellent link on how to replace it yourself .

http://www.saltedwound.com/archives/2007/04/24/repair-service-4wd-light-on-2000-chevy-silverado/

i know its a siverado but its the same process . that will fix ya !

There is a small hole at the base of the headrest post. Use a nail and push in the hole to release them.

Park your car in a safe place with a level surface. Turn off the ignition switch, all electrical accessories and open the hood.
Disconnect the black negative battery cable. Remove the mounting bolt from the engine oil dipstick tube, using a wrench or ratchet and socket. Move the tube to the side.

Raise the front of the vehicle, using a floor jack and safely support it on two jack stands. Remove any under-engine cover shields, if your model is equipped with them.
Remove the mounting bolts from the transmission plastic cover and remove the cover. If your model is equipped with a starter-to-transmission cover, remove the bolt. If there are any sensor electrical connections that might interfere with the starter removal, unplug them now. On some models, you might have to disconnect the engine oil level sensor.

Remove the nut from the front axle mounting bracket through-bolt using a wrench or ratchet and socket, if you have a 4WD model; then pull out the through bolt until the tip is flush with the support bushing, but do not remove the bolt.

Remove the two starter mounting bolts using a ratchet and socket. On some models, the starter is mounted with a short and a long bolt; make a note of the bolts' locations.

Pull the starter forward until the motor clears the transmission and remove the starter-to-transmission cover. Disconnect the battery cable and wiring harness from the starter solenoid on top of the starter, and remove the starter from the vehicle.

To install:
Set the new starter in place and connect the battery cable and wiring harness to the starter solenoid. Set the starter-to-transmission cover in place and install the starter mounting bolts.

Seat the front axle mounting bracket through-bolt back in position and tighten the nut. Plug any sensor connectors you might have disconnected previously. Install the starter-to-transmission cover bolt and any other protective shields or covers previously removed.

Lower the vehicle. Install the bolt to the engine oil dipstick tube and connect the black negative battery cable.

Hope this makes some sense, harder to explain the show. Good luck friend and be safe.

These instructions are for the regular size Yukon, but hopefullly will apply to your XL. Despite what you may read elsewhere it is virtually impossible to access the pumps and fittings without releasing and lowering the reservoir. Release the four plastic retainers at the forward side of the left front inner fender, working in the wheel well. Note that two of these fasten to the reservoir. Then remove the battery [I have read elsewhere that you should remove the negative first then wait a minute before removing the positive, something to do with air bags ??]. Remove the 6 cap screws that hold the battery pan in place, and a seventh that supports the reservoir from the top. Remove the pan. There are two more screws holding the resevoir, one near the filler cap and the other near the passenger side of the bottom - access this from below or from wheel well, pulling back the inner fender that you have freed earlier. The reservoir will now drop down so unless you have emptied it you should support it so as not to strain wires or hoses. Now you can access the wires and hose fittings to release them and then the pumps. The pumps are just a press fit into a rubber bushing that fits in to the hole in the reservoir. Be sure to get the new one properly aligned - if you look at the design you will see that a peg on the top fits in to a slot in the resevoir. Reverse the above to reassemble. Check the hoses carefully to be sure they are not cracked or damaged or you will be doing this all over later. The hoses pass through slots on the side of the reservoir that seem perfectly designed to put nicks in the side of them, especially if you have put strain on them, and this guarantees they will fail later. If you have to repair a hose you will find it easier to make a coupling from some 7/32 rubber hose than to try to replace the original .hard plastic hose. Good luck.

TRY LUCAS OIL,I USED A FULL LITRE FIRST,WILL LET YOU KNOW HOW IT WORKED.BEFORE THIS I CHANGED OUT TWO ROTTEN LOOKING KNOCK SENSORS,THEN TWO WEEKS LATER REPLACED THE REAR ONE AGAIN,AND IT FAILED AGAIN.AND SO I AM NOW TRYING THIS NOTICED A BIG DIFFERENCE IN POWER NOISES,NO PINGING,NO RATTELING LIKE IT IS A DISEL.

The most likely cause of your code is a bad rear knock sensor. You should check the knock sensor wiring harness for corrosion. But if that checks out the sensor will have to be replaced. The knock sensor is under the intake manifold, although it's not too difficult to remove. Both knock sensors should be replaced along with the wiring harness, just because of labor involved in gaining access to the sensors. You could try clearing the code, it may stay off for a long time.

Hi, depending on the vehicle, there can be different controls. Standard control, 4hi, use in slippery conditions, never on dry pavement. Just push the button, and it will engage. 4low is for extreme conditons and the transmission must be in neuteral to engage 4lo. If you have auto 4wd button, just press the button in slippery conditions. If you have a denali, it is all wheel drive, and there are no buttons to push. So, depending on the model, there are multiple ways, but pushing the button engages it. Good luck...Goop

my 2001 yukon xl 2500 with the 6.8 keeps overheating only with the ac on while is in park or on a stop.
help please.

Should be the same as the 99
http://www.2carpros.com/forum/automotive_pictures/139033_nnnn_2.jpg

In the under hood junction box , fuse CTSY LP 15 amp . Instrument fuse panel PWR WDO CB 25amp .
Sunroof Motor Synchronization
Synchronization will be necessary anytime the sunroof module battery positive voltage circuit is interrupted. The sunroof module will be synchronized when the controller learns the full vent position. The sunroof system will ignore any open request until the system has been synchronized.
To synchronize the sunroof:

1. Turn ON the ignition, with the engine OFF.
2. Using the close/tilt up portion of the sunroof switch, operate the sunroof glass until it reaches the full vent position.
3. Verify that the system operates normally.

Once the sunroof glass reaches the full vent position, the actual position is stored in the memory of the sunroof module. The sunroof module will stop the motor one motor revolution before the defined actual positions
Hope this help ! good luck !