2004 Denali 4 wheel drive questions

[flaglor]

Hello. I have a 2004 Denali with 193,000 miles. I bought it recently and am sorting out the issues. The automatic stability system was in rough shape, so I replaced the air ride shocks with 4 new Bilsteins that were sold as a replacement for the Denali air system. Rides good now.

Currently have ABS and Traction Control indicators on at all times. Also have Service Stability and Service Ride Control as indications on the dash. I would imagine that the Service Stability and Service Ride Control will stay on forever, as I went around that system with my normal shocks.

I am still having the ABS light illuminated all the time. I suspect the ABS control module is bad, but I wanted to ask if my conversion to standard shocks might have had any effect on the ABS system?

How can I tell if the 4 wheel drive is actually working in this vehicle? What is the Traction Control indicator telling me?

Any advice or education greatly appreciated! I'm a mechanic, but obviously not well versed in these systems.

 

[adventurenali92]

the service suspension messages ar w flashing because they computer is not detecting the electronically dampened auto ride shocks. You will need to wire resistors into the harnesses for the auto ride shocks that make the computer think they are plugged in. Not sure which ones you need but there are members here that have done it and can chime in. As far as the other issues you need a bi-directional scan tool to properly see what issues are coming from what modules. Otherwise you’re taking shots in the dark trying to address those issues.

As to your 4WD question your Denali is not 4WD. It is a full time all wheel drive transfer case. It’s in all the time and the stability system will kick in when it detects wheel slip via the wheel speed sensors and will apply power to their wheels not slipping to give better traction.

 

[B-train]

Agreed with @adventurenali92 . Those years were prone to corrosion on the wheel bearing and throwing off the sensor reading. One bad wheel speed sensor will disable the whole system.

You can test the AWD on some snow or mud. Lean on the go pedal and as the resr wheels slip you'll feel the front wheels engage.

The one benefit to the Traction control fault is you can have all the fun you want in the snow without rhe fun police stopping you.

 

[flaglor]

Thank you for the explanation. I will take it somewhere and have the wheel sensors checked!

 

[TollKeeper]

Since you are a newbie, you dont have your profile filled in. Depending on where you live, one of the members here (like myself) can meet up with you, and scan it for a better price than any shop.

So where do you live?

Autozone/Advance/ORiellys/NAPA cant read those codes.

 

[flaglor]

Hello! I did get out today and verify that the 4wd is definitely operational. Fun! I have the Traction Control, ABS, and airbag lights on continuously. I guess those are the next things to troubleshoot. The new shocks, front suspension wear parts, and alignment that I did really made a great difference, and the truck is nice to drive. Engine runs fine, although I get the code for the mass airflow sensor after driving it for about 20 miles. I can reset it but it always comes back. A replacement sensor is not expensive, so I guess that will be another thing to change out soon.

The ABS light stays on all the time. It looks like a replacement controller is about $275. Can anyone think of anything to check before I spring for one? My local mechanic scanned it when doing the shock swap and felt like the controller was probably the issue.

Any thoughts on first steps for solving the Traction Control issue?

Thanks! Tom

 

[Dlayne]

If I remember correctly, from my vehicle of that year, as someone mentioned earlier, brake sensor was my issue. Replaced and all was good. If you are depending on the AWD for winter driving. The traction control should be addressed as the AWD system is interconnected.

Good luck.

 

[flaglor]

Ok. Thanks. The reason for this vehicle is to haul my family up the mountains in NC during bad weather, so the 4wd is important for sure. I will get a scanner on the brake sensors.

 

[flaglor]

Looks like there is an "ABS Wheel Speed Sensor", along with a sensor that is included when you purchase a "replacement wheel bearing and hub". Is the first just the sensor, minus the hub, or are they two different sensors?

 

[flaglor]

Update: I took my Yukon in and had the wheel sensors checked. All were working correctly. Shop advised that the issue is probably the bad ABS control module. They felt that the ABS module would affect the Traction Control if it was not working. I am going to put the truck on the lift tomorrow and pull ABS module off to verify the part number.

There is a service that repairs your ABS module and returns for $140. Upfix is the name. Has anyone used them?