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  1. #1

    Default "Service 4WD" when I go from Auto 4WD to 2WD

    Howdy,

    I've got a 2003 Yukon XL. I don't use the 4WD mode much, but lately we've had a lot if ice and snow and in our neighborhood there is still a lot of ice. You have to drive slow and there's plenty of slipping and sliding. I put it in Auto 4WD because based on my understanding of the different modes (Auto 4WD, 2WD, 4HI, 4LO) that is the most appropriate for variable conditions like icy roads that may have some exposed pavement.

    My DIC is now giving me a "Service 4WD" message when I go from Auto4WD to 2WD. The manual for my vehicle describes this error message as follows:

    If a problem occurs with the all-wheel drive system this message will appear on the DIC. If this message appears, stop as soon as possible and turn off the vehicle. Restart the vehicle and check for the message on the DIC display. If the message is still displayed, or appears again when you begin driving, the four wheel drive system needs service.So, I turn the vehicle off, and turn it back on again, and the error disappears. Until the next time I go from Auto4WD to 2WD... so what's going on? Any suggestions?

    -Josh

  2. #2

    Default

    Quote Originally Posted by jbeall View Post
    Howdy,

    I've got a 2003 Yukon XL. I don't use the 4WD mode much, but lately we've had a lot if ice and snow and in our neighborhood there is still a lot of ice. You have to drive slow and there's plenty of slipping and sliding. I put it in Auto 4WD because based on my understanding of the different modes (Auto 4WD, 2WD, 4HI, 4LO) that is the most appropriate for variable conditions like icy roads that may have some exposed pavement.

    My DIC is now giving me a "Service 4WD" message when I go from Auto4WD to 2WD. The manual for my vehicle describes this error message as follows:

    If a problem occurs with the all-wheel drive system this message will appear on the DIC. If this message appears, stop as soon as possible and turn off the vehicle. Restart the vehicle and check for the message on the DIC display. If the message is still displayed, or appears again when you begin driving, the four wheel drive system needs service.So, I turn the vehicle off, and turn it back on again, and the error disappears. Until the next time I go from Auto4WD to 2WD... so what's going on? Any suggestions?

    -Josh
    Hi Josh,

    You will need to have your transfer case module scanned for trouble codes. The code will tell you which component of the system is at fault.
    Jim

    2004 SILVERADO 2500HD LS
    Pro Comp Leveling Kit
    285-75-16 Cooper ST All Terrains
    Pro Comp Programmer
    Bilstein Shocks
    Linux Bed Liner
    Tinted Windows



    Other rides:

    1967 Landcruiser <350 Chevy>
    1970 Camaro
    1990 Geo Metro Convertible
    2007 FJ Cruiser

  3. #3

    Default Can I do that with a regular ODB II scanner?

    Quote Originally Posted by Jimmiee View Post
    Hi Josh,

    You will need to have your transfer case module scanned for trouble codes. The code will tell you which component of the system is at fault.
    Can I do that with a regular ODB II scanner?

    I have a friend that has one I could borrow, and Autozone will do a scan for you for free. I'll be out tomorrow, I could stop by Autozone.

  4. #4

    Default

    Quote Originally Posted by jbeall View Post
    Can I do that with a regular ODB II scanner?

    I have a friend that has one I could borrow, and Autozone will do a scan for you for free. I'll be out tomorrow, I could stop by Autozone.
    Unfortunately an generic scanner will only read generic codes. It can't see specific codes like the transfer case, ABS, body codes, etc.

  5. #5

    Default

    ya you will have to get a specialized scanner or a complete automotive scanner that mechanics usually use to read those.
    1997 K1500 Silverado 4X4. Black Exterior, grey/black interior. 35X12.50X15 wheels and rubber, ProComp 6inch lift 6 shocks in the front 2 in the rear, 3 inch body lift, a few cosmetic mods. Nothing major. Custom leather interior, and stereo upgrade is the future mods.


  6. #6

    Default

    Well, it got better (it stopped saying "Service 4WD" after I went in/out of Auto 4WD/2HI), and then it got worse just tonight. Merry Christmas, eh?

    We were out today visiting family for Christmas. I got the "Service 4WD" message after I switched from Auto 4WD to 2HI, and unlike the previous times, when I turned the engine off and then back on, the message did not go away. Additionally, the lights on the transfer case buttons were all off (normally it has a light next to the mode you're in--e.g., Auto4WD, 2HI, 4HI, or 4LO).

    Fortunately we were close to home, and so I decided to just drive home and check in with the local dealership tomorrow morning (if anybody is there). On the way back home, at about 40mph, I suddenly started getting a rattling/grinding sound--just as I noticed the light next to "4LO" came on. I immediately put the transmission in neutral and slowed down to a stop, then hit the 2HI button. It clanked once and then all returned to normal--no more grinding sounds, and it felt normal when I lightly stepped on the gas to accelerate back up to speed.

    I drove it the rest of the way home and I will check in with the service station at the dealership we bought it from as soon as I can get ahold of somebody... hopefully nothing got seriously damaged :-(

    Naturally, I'm interested in any additional feedback as to what might be going on, and what I should tell the technicians to check into.

    -Josh
    Last edited by jbeall; 12-25-2009 at 11:26 PM.

  7. #7

    Default

    I talked to the owner of the dealership (where we bought it) this morning. None of their technicians are in today (I can hardly blame them, it's the weekend and the day after Christmas ), so we'll have to drop it off Monday morning to get it looked at.

    I described the problem to him and his advice was, in essence, that we can drive it if we need to, but leave it in 2HI (don't switch to any of the 4WD modes).

  8. #8

    Default

    They will scan it and the codes will help them pinpoint the problem for you.

  9. #9

    Default

    They said it was the "encoder sensor" that controls the motor that moves the transfer case into the various different modes.

    It was $100 for the part and $120 labor for the repair (total $220, plus sales tax, which they charge on everything here in WV...).

    It's been several weeks and so far so good...

    Was that price fair? I didn't really have time to shop around, I needed my truck fixed.

  10. #10

    Default

    Dude;

    I think you got off cheap. (and lucky)
    We had the same thing happen with our '05 Z71 Tahoe. Saving to replace the transfer case. Every time I try to move more than a coupe of feet a LOUD grinding noise comes from the transfer case. We had the same symptoms as you. The noise is not too bad going forward. But when going backwards it sounds as though the Earth is pulling it's self apart!

    Good luck.

    Craig

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