1999 suburban 4x4 service light

[Zorad1000]

After the vehicle sits overnight, the first time I start the engine , the service 4wd light comes on and stays on until it idles for several minutes. Also the 5 lights on the 4x4 switch stay on as long as the service light is on . After the lights go off the 4x4 works perfectly fine. Just wondering if anyone has had this problem before? I suspect the front axle actuator is the problem. What do y’all think?

 

[zora]

That is a possibility but you need to have it scanned to determine the code being thrown.

 

[Zorad1000]

That is a possibility but you need to have it scanned to determine the code being thrown.

Thanks . Just wondering is a ‘99 a year model that I can read codes by grounding a pin on the ALDL and reading the flashes , or do I have to use a scanner . I read on another site that on some years you can ground pin 13 and do this . My vehicle doesn’t have a wire in pin 13 . Have you heard of anything like this?

 

[zora]

OBD1 you could do the paper clip trick. Most cars had OBD2 by 1995. Look at the emissions stickers under the hood, I suspect by 1999 you would have OBD2,

 

[Zorad1000]

Yes it is OBD2 . I just didn’t know if this was some kind of special diagnostics for the 4WD system. Thanks for your help. I’ll post again when I find out the code . Funny thing is that I’ve been driving it today and the service 4wd light hasn’t come on at all , except when the key is first turned on.

 

[Zorad1000]

Yes it is OBD2 . I just didn’t know if this was some kind of special diagnostics for the 4WD system. Thanks for your help. I’ll post again when I find out the code . Funny thing is that I’ve been driving it today and the service 4wd light hasn’t come on at all ,
except when the key is first turned on.
-So I finally found someone with a scanner that would scan the 4wd system. As it turns out, the 4wd system apparently does not store codes . If the light comes on and then goes off before you can scan the vehicle , the codes will be
erased . At least on a 1999 Suburban.....The light hasn’t been on all day. Thanks for your help anyway.

 

[Zorad1000]

The problem has gotten so bad that the lights are always on and it is always in 4 wheel drive . I can take the fuse out , put it back in and the lights go out and the 4x4 works as it should . I discovered that the TCCM doesn’t store codes like the ECM does . So it is difficult to get to the transmission shop to get it scanned because every time I tried , the lights would go out . I’ve decided to replace the TCCM because as I’m inserting the fuse I can hear some clicking in that area . I’ve also heard some unusual noises in that area when driving lately .

 

[zora]

Ok, good luck. A little puzzling in your first sentence you say it is always on but later you say it goes out if you try to go to the shop.

 

[Zorad1000]

Ok, good luck. A little puzzling in your first sentence you say it is always on but later you say it goes out if you try to go to the shop.

Sorry for the confusion, I guess I should have said that the times I’ve either gone to the shop or tried to go to the shop The lights went out . The past few days the
lights are on all of the time and 4x4 is engaged . I really don’t like driving on dry pavement like that so I didn’t try to go to the shop this time
and with all of those unusual noises coming from the area of the TCCM I just decided to replace the thing . I don’t remember what they charged me to scan it the first time but I don’t think it would’ve taken long to pay for the rebuilt TCCM . Thanks for your interest and help .

 

[Zorad1000]

So I replaced the transfer case control module (TCCM) . the 4x4 is now working as it should, also the unusual noises under the dash have stopped .

 

[zora]

Thanks for the update. Where did you find the TCCM?

 

[Zorad1000]

Thanks for the update. Where did you find the TCCM?

It was located near the steering column Under the dash . it was easy to get to but because of a nearby wiring harness it was difficult to unplug . It has a black connector and an orange connector. The YouTube video I saw showed it being near the tach so that was the first place I looked but it wasn’t there...I bought the rebuilt TCCM at O’rileys auto parts . It is a Dorman part .