Jump to content

Recommended Posts

Posted

So, yesterday afternoon, I jump in my tuck after running errands. service notice flashes says "service 4wd" I dis miss this, check my 4wd knob and its in AWD, where it stays unless I need 4wd. I go to back up and turn and its clear Im in 4wd. Cannot get it out of 4wd. Tried running through 2wd/4hi/4lo etc. nothing no shifting at all. I drive a lot so my truck is at about 54K (its a 2015, bought in 2015) and I have had no issue with it so far. great truck. no complaints. So, I drive into town today, call the dealership (who at first said they couldn't look at it till Tues- wed) they eventually say they can squeeze me in today around 2. Great! I think this is great. Still under warranty, if it has to be messed up better now then in 6k more miles right!- but wait. looking up their warranty the most likely culprits (wiring, tccm etc) aren't covered under warranty. Really. with so many others having this problem?... I can accelerate and drive it, turns are irritating. Seeing that there aren't any real "fixes" for this since 2014 not a good start to this week. Anyone find anything that seems to have stopped this action from reoccurring?

Posted

I wouldn't run it in AWD all the time.

2WD would be my choice.

:happysad:

Posted
4 hours ago, Macken0310 said:

So, yesterday afternoon, I jump in my tuck after running errands. service notice flashes says "service 4wd" I dis miss this, check my 4wd knob and its in AWD, where it stays unless I need 4wd. I go to back up and turn and its clear Im in 4wd. Cannot get it out of 4wd. Tried running through 2wd/4hi/4lo etc. nothing no shifting at all. I drive a lot so my truck is at about 54K (its a 2015, bought in 2015) and I have had no issue with it so far. great truck. no complaints. So, I drive into town today, call the dealership (who at first said they couldn't look at it till Tues- wed) they eventually say they can squeeze me in today around 2. Great! I think this is great. Still under warranty, if it has to be messed up better now then in 6k more miles right!- but wait. looking up their warranty the most likely culprits (wiring, tccm etc) aren't covered under warranty. Really. with so many others having this problem?... I can accelerate and drive it, turns are irritating. Seeing that there aren't any real "fixes" for this since 2014 not a good start to this week. Anyone find anything that seems to have stopped this action from reoccurring?

Let me know what you find out

Posted

Scan showed c0398 code- transfer case control module- tsb outlines that if you have a c0398 code you've probably also had/have c0392 and c0396 codes, i believe. That might not always be the case. They checked for updates and cleared the code. They did cover it under warranty and it's currently in 2wd and working normally, however, I haven't tried switching between 2wd/4wd and I've left it in 2wd instead of awd. (Other post say to leave it in 2wd unless 4wd is needed then be sure to switch back to 2wd before turning truck off-so im trying that logic). This fixes it today, but isn't signed off as a permanent fix by dealer. 

Posted (edited)

When DTC C0398 sets, the vehicle is permanently locked in 4HI and cannot be shifted out of it while the code is present. This is a software problem. The fix is a software update. Had my 2015 updated and no more problems. It is service update 28770.

 

See this...

 

https://gm.oemdtc.com/7291/28770-service-update-4wd-ips-drift-dtc-c0398-4hi-lock-up-2015-2016-cadillac-chevrolet-gmc

 

Edited by Mr. Z71
remove duplicate wording
  • 10 months later...
Posted

I have a 2015 Silverado 1500 and just had to deal with the "service 4wd."  It seems that driving in "auto" for more than 1.5 hrs can cause this issue. We had a terrible rain storm a few days ago and I was stuck in traffic for 2hrs with the "auto" selection on. I didn't realize there was an issue until I tried turning into my driveway, it felt like I was in 4wd. After reading numerous posts I tried everything, disconnecting the battery, pulling the 30amp 4wd trec fuse... and nothing worked. I took it to the dealer and they had to reprogram the TCCM. 2 codes came up: C0398 and U0403. I got tagged $130 for the diagnostic fee but that included the reprogramming. I hate having to go the dealer but didn't have any other choice and I'm out of warranty so I ate it. Going forward, I was told to avoid this issue again, don't drive for more than an hour in "auto" and when you are shutting the truck off put it back in 2wd.. hope this helps

  • 5 years later...
Posted

I have the same problem with my 2016 Sierra . I watched a u-tube video on how to reset the computer & clear the 4x4 service light . I followed the instructions & got it working ! Of course I didn't write down the procedure & now I can't find the video ! Now that I see what issues other people are having ; I can see where I'm going wrong . Apparently you MUST shift to 2 wheel drive BEFORE you shut the truck off !! Talk about stupidity !! If & when I get this system reset I will definitely pay attention ! Thank you for all the great info !

  • Thanks 1
  • 10 months later...
Posted (edited)
On 10/30/2017 at 6:51 PM, joshc64311 said:

2015 Silverado 1500 5.3 4x4 service light. In the power link box I pulled the fuse number 6 I heard the transfer case engage and put it back in and it reengaged but it fixed the service 4wheel drive not sure how long it will be fixed but I was able to take it from 4h to 2wd. Might help someone

 

Edited by Anthonywar
  • 4 months later...
Posted

So are these problems that happen in cold weather?  I have been experiencing similar problems but only in cold weather and a older battery?  And have had simpler codes of low voltage show up.  Is it as simple as replacing the battery that can keep enough amps going to everything that is constantly drawing power?  I am asking for any and all input.  I am obviously going to rest the computer and replace the old battery.  It starts fine but I have seen weak alternators cause a lot of problems.  And yes I am a experienced heavy equipment mechanic and welder.  So let's have real conversations please 

  • 10 months later...
Posted

I have a 2015 Sierra and about 3 weeks ago it got really cold ended up needing to get a new battery and that’s when the service 4wd code came up . I got on here and someone posted about the number 6 fuse and it work . Thanks 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Latest Articles

  • Posts

    • I just can't think of the exact term GM uses for that higher gvw package without looking at the website but basically sort of a trailering package and I imagine it may also have been created to skirt around the licensing fee differences between a3/4 and 1 ton that apply in some states although ironically I believe in some states its the reverse that a 1 ton is the cheaper truck to license over a 3/4 ton. It makes no difference here in Alberta but oddly enough a 1 ton through my insurance company is a bit cheaper to insure over a 3/4 ton as its based on the insurance statistics they generate.    For sure when ever you do have the chance to weigh your truck and to be fair, try to have the fuel tank full or nearly so rather than give yourself a false sense of the truck being lighter by having an almost empty tank.    In my other comment I was mentioning stock sized tires and partly in case someone was reading this and thinking they could lower their pressure down to what your aftermarket tires are able to do with your empty truck as that is a vastly different picture in the leeway you have to play with for running minimum pressures while remaining safe. I will say also that its easy to see from reactions of truck owners that may have been more used to owning a half ton in the past or a car and be it on a forum like this or in person etc that they get so wrapped up in that placard pressure sticker that they can't get their head wrapped around the fact that an HD truck due to how much it can carry can also vary the tire pressures drastically lower than those pressures ( typically more so for the rear axle on stock sized tires ) when empty vs some car that isn't made to carry much so the tire pressures can't be lowered since it needs almost that much pressure just to carry the empty car.    If I ever do find myself in the states with this truck, I will only be too happy to switch it over to the US measuring system as then I will understand all the dash readings. The only thing that is off for me slightly with US measurements is US miles per gallon as I grew up with the Imperial gallon and to this day up here anyway speak in Imperial miles per gallon ( I don't do that on this forum though as that would confuse everyone for no good reason ). 
    • Yes that's right, it's the upgrade that includes the overload spring and all that stuff.   Someday when I'm empty and going by a scale I'm going to stop in and get some weight readings.   Exactly  you should have the ability to change individual settings, in in Canada so I'm driving with kph but then I'm stuck with kpa when I want psi lol    
    • You must have that upgraded gvw package which is only available or at least was in 2025 with the diesel engine for the 3/4 ton and that gave the truck physically the larger 12.0 ring gear rear diff and the 3500 rear spring pack. There is a difference in what the diff housing looks like externally as one tell tale and also your truck should have the upper overload spring pack and the frame pads that the pack goes up against.    The pressure the tpms system kicks the alarm in on a stock setting truck, that is a good question and was just from what I recall but I doubt I made any notes on it as I knew for the rear that it was not at all what I was after regardless either. Being that you have a diesel and if running on stock tires the minimum pressure on an empty truck seems to be around 50 psi from hearing of those that have weighted the front axle but the rear axle is very similar in weight to a gas truck and again a near empty truck on the rear could go down to 35 pounds at minimum. However the weigh scale is the proper way to know for sure as a guide.    As to changing the readings on the dash from metric to the US measuring system, oh yes that is done easily but what I was attempting to explain was that I can't pick and choose items I want to have in US and those I still want in the metric system at the same time as its either all or none. For example lets say you drove into Canada and switched your dash over to metric so your speedometer read in km an hour, well then your reading kilopascals on your tpms readout and your wife looks over and says what the hell is that saying in the tpms screen and you say "darned if I know, I think its Chinese" !
    • This is partly why I decided to have switched over to Amsoil SS as a way of hopefully preventing the buildup of the sludge/carbon on the pistons and clogging of the oil control rings and the carbon that would cause the compression rings to stick in their grooves as well as stay cleaner up top of the heads in the valve train in the first place, an oil that has tested better by third party testing over typical shelf oil and also doing my best to run relatively short OCI. However in saying that I don't think there is any way to easily prove the oil I was using prior allowed for a buildup at the OCI I was doing, nor in the other direction to make claims the Amsoil is keeping everything clean either. There really isn't a window into the engine is there to know anything for certain even if oil samples were taken for example that showed still healthy oil being dropped out of the oil pan other than engine tear downs that extensive and expensive testing of oils does to actually visually see what is really going on inside the engine. I wish there was some easy method of seeing what is going on but I don't happen to be aware of that if there is.  
    • My truck is a ¾ ton but my placard also says 80 for the rear tires, I think I might have the upgraded suspension to the 3500 series maybe.   I put my air down to 60 and the light was still on, and there was no way I was putting over 60 psi in the rear empty and not towing because I knew the actual number Toyo gave me and I didn't wanna ruin the center of my tires!   And you actually can change it in the settings from metric or is and it will show kph or mph then when you go into your tire settings it will be either psi or kpa, but it would be nice to just change it directly on the tire psi page 
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...