Service 4WD - Stability System Disabled warning

Discussion in 'Chevy Tahoe Forum (GMC Yukon, Cadillac Escalade)' started by tdj2591, Dec 30, 2013.

  1. tdj2591

    tdj2591 New Member

    Help! Whenever the temperature drops into the 30s (usually with frost) or often when it rains, I get alternating "Service 4WD" & "Stability System Disabled" warnings on my Tahoe DIC. When this happens, none of the lights are on for any of the Auto/2WD/4WD switches. Sometimes the warnings will go away and the 2WD switch light returns if I shut off and restart the engine. Today, only the 4Low light was on and could not be switched off or changed to 2WD even with a restart. Engine power was way off but the Tahoe did not seem to be in 4WD. When I started it hours later, it was in 2WD again and working normally. This problem is intermittent but appears almost every cold morning. I'm beginning to think there might be a short that occurs whenever certain wires are wet. If so, any idea where the wires might be located? Any ideas what else might be causing this? Could low fluid level cause this (I doubt the level is low). If the actuator, where exactly is it located and how difficult is it to replace?

    2005 Z71 Tahoe - 114,000 miles - 4WD rarely ever used - transfer case fluid has never been changed
  2. ElbowJoe

    ElbowJoe Member

    Hey tdj2591. I have an '03 Suburban that has had issues with the "Service 4WD" light and also the lights on the buttons on the Transfer Case Selector Switch. My truck will periodically change to 4 HI or 4 LOW on it's own and sometimes all the lights will light up on this switch.

    I did a fair amount of research on this subject and found that the transfer case selector switch had some issues in the early '00s of the Suburban/Tahoe/Yukon. It seems that some solder joints get cracked and make/break contact. I just ordered a new selector switch from It was much cheaper than a dealer. The swap out of the switch is very simple and can be done in about 10 minutes.

    I am still waiting for my part and it should be here today. I will let you know how it goes.

    Also - it is a good practice to put your truck in 4HI and 4LOW and drive it a mile or so a couple of times per year just to exercise the 4WD system to ensure proper lubrication and function.

    Finally - change that T-Case fluid! It is a simple job. Hopefully your rear diff and tranny fluid has been changed. If not - you had better get on that as well. I usually have the tranny fluid changed along with a filter change professionally. The rear diff can be changed fairly easily by yourself if you are so inclined. I strongly suggest synthetic lube in the diff case and the t-case.
  3. tdj2591

    tdj2591 New Member

    Thanks Joe

    i had the fluid changed in both diffs and the transfer case this morning with full synthetic. Going Bach this afternoon to have the tranny filter and fluid changed. They were unable to find any codes. The warnings were, of course, off when I took it in. They usually go away when the engine warms up and I do a restart. They said they have replaced a lot of actuators in trucks having this problem, so that might be my next step. They said they had one in last week that shifted into 4LO by itself while on the road and caused much damage.
  4. tdj2591

    tdj2591 New Member

    Thanks for the advice. Today, I had the fluids changed in the F&R diffs and the transfer case along with tranny fluid and filter. Used synthetic in TC and Diff. They were unable to pull any codes as the warning message was off at the time and no codes were stored. They said they get lots of trucks with this problem and the cause is almost always the actuator. They said they had a customer last week whose truck shifted into 4LO while being driven and it caused a lot of damage. I still wonder if my problem might be an electrical short. From what I've read, it sounds like the problem with the dash switches was in earlier models.

    Let me know how your repair goes.
  5. tdj2591

    tdj2591 New Member

    Interestingly, after the TC fluid change, the warning messages have not reappeared. But, it has been dry since then despite single digit weather temperatures. So, I don't know if the new fluid fixed it, if clearing all the codes helped or if rhe warnings might reappear the next time I drive in rain. We'll see.
  6. ElbowJoe

    ElbowJoe Member

    tdj - I hope you are still error free and enjoying your Tahoe!

    I just wanted to give you an update. Since I swapped out the transfer case selector switch, I have not had any "SERVICE 4WD" messages nor has my selector switch lit up like a Christmas tree or thrown me into 4 HI or LO. I need a few more weeks to be sure this is totally solved.

    For now I am keeping my fingers crossed.

    BTW - I also changed out 2 of my audio controls on my steering wheel due to the back lights burning out. I wasn't sure how difficult this was going to be - but it ended up being pretty simple in case you need to do it.
  7. tdj2591

    tdj2591 New Member

    Glad the fix worked for you, Joe. Well, today it rained and guess what, the Service 4WD message reappeared. I fell that it has to be an electrical short since it seems to be triggered by moisture. Any idea where to start looking for a short?

    I also have a rear window that will not operate. Haven't tested the switch and am not sure how to get to the switch or to the window relay/motor.

    Good job on your audio/steering controls. I'm always concerned that I might trip the airbags when I mess around inside the steering wheel. If I have to get into them, I'll sure reach out to you.
  8. ElbowJoe

    ElbowJoe Member

    Well tdj - my luck has run out. :grrrrrr: The issue is back. I am getting both the SERVICE 4WD error message on the dash regularly and the issue of the transfer case having a mind of it's own and jumping into 4 LOW has happened at least 2 times in the past couple of weeks.

    I am hoping you have found something out than may be helpful.

    I plan to climb underneath to check the wires near the transfer case - but this past week we have record low temps (-16 on Thursday). Perhaps it will heat up in the next week or so.
  9. tdj2591

    tdj2591 New Member

    If this is a duplicate response, please disregard. I don't see my earlier response.

    A few weeks ago mine was in 4L when I started it. Drove it a mile then stopped and tried switching into 2H. Tried everything, slowly moving, stopped, in reverse, restart. Finally, it made two loud clunks and switched into 2H. No problems since then but I've been afraid to try and switch into 4H or 4L. I'm wondering if the noise was the actuator braking or fixing itself. Haven't yet been able to get underneath to check for wiring short. Let me know what you find out about yours.
  10. the phantom

    the phantom Epic Member 5+ Years ROTM Winner 1000 Posts

    Not sure if this is an issue with your guys wiring but when I was researching a similiar problem with my escalade I found someone posting that the wiring down by the drivers side left foot area may be getting wet. (possibly a connector??) I guess its in the corner under the carpet. If I remember right it was the wiring that ran to the body control module. or ebcm Hope you figure this out.. Electrical problems suck on vehicles!!!

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