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Fix_It_Man
Fix_It_Man, ASE Certified Technician
Category: Oldsmobile
Satisfied Customers: 17278
Experience:  I am an ASE Certified Master Technician and auto repair specialist with over 16 years of Oldsmobile experience.
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I have a 2001 Olds Bravada 4.3 AWD. The AWD light

Customer Question

I have a 2001 Olds Bravada 4.3 AWD. The AWD light intermittently goes on and off, The weird thing is the front wheels still spin when light comes on. Are these things vacuum operated like the older s-10 blazers when the vacuum line under the battery would
always go bad? I am lost and don't want to spend $150 on a new encoded motor if it doesn't need it.
Submitted: 1 year ago.
Category: Oldsmobile
Expert:  Fix_It_Man replied 1 year ago.

Hello, my name is***** for the question. Typically this happens because the computer is picking up a bad speed signal from one of the wheel speed sensors. It may be a failing sensor or a mismatched tire. If one of the tires is even slightly different tread wise then this will occur. If all of the tires are exactly the same then it may be a speed sensor. Please let me know if you need more help.

Customer: replied 1 year ago.
I said AWD. Not ABS. All tires are brand new and all 4 match. All speed sensors show and read fine. Front wheel bearings were replaced with new sensors. Rear was done as well and same problem exists. I believe the code was a co310. Would have to look in the morning to verify it.
Customer: replied 1 year ago.
All wheel drive issue.
Expert:  Fix_It_Man replied 1 year ago.

The all wheel drive system also reads speed info. Does the light seem to come on under certain driving conditions.

Customer: replied 1 year ago.
Hard to tell really. Just on for most part, go's off intermittently
Expert:  Fix_It_Man replied 1 year ago.

Have you checked the connections at the encoder for signs of corrosion it water intrusion? I typically remove these connections and clean them with electrical cleaner and place dielectric grease on them and reinstall them.

Customer: replied 1 year ago.
I just did that today and greased them. They weren't really dirty. Still no change.
Expert:  Fix_It_Man replied 1 year ago.

Do you get any noise at all from the transfer case or the front differential?

Customer: replied 1 year ago.
I'm not sure what you mean by noise. I will have to continue in the morning when I get to the shop. I am hitting the sack.
Expert:  Fix_It_Man replied 1 year ago.

Let me know. Just wondering if there is any popping or grinding noises when the AWD kicks in.

Customer: replied 1 year ago.
No noises what so ever
Expert:  Fix_It_Man replied 1 year ago.

I would pull the front differential actuator and see if it appears to be stripped. It is more common than the encoder.

Customer: replied 1 year ago.
I can check it in the morning and get back to you.
Expert:  Fix_It_Man replied 1 year ago.

Sounds good. I will look for your response tomorrow.

Customer: replied 1 year ago.
I wasn't able to get back on the bravada until a little bit ago, it doesnt have a front actuator on the front diff.
Expert:  Fix_It_Man replied 1 year ago.

Have you changed the fluid in the transfer case? If you did, how did the fluid look?

Customer: replied 1 year ago.
The fluid has nothing to do with the encoder motor not getting power. But, Yes, I have changed the fluid out and flushed it.
Expert:  Fix_It_Man replied 1 year ago.

I ask just because of transfer case failure. You need the encoder. From the code you are getting and if the connections are fine then the encoder needs to be replaced.