ABS, Traction Control & Stability Control Lights

I have a 2008 Gran Prix GXP with 50k on it. It seems when it rains or snows the ABS, Traction Control & Stability Control messages popup on the screen saying the need service. When this happens they all stop working, but when its dry out they work fine. Where should I start looking for a loose connection at? Or what could it be?

Thanks!

First thing to do is to see what code(s)are stored. You can do a visual of the connectors at each speed sensor and check for water intrusion, and check for any obvious damage on the sensor harnesses.

check for a damaged or missing rubber bushing/seal at one of the bearing connectors. If they have been unplugged in the past the part may have fallen out. If it did the connector will move around too much or get wet and set the lights off.

The dealer scanned it and said it both front hubs are bad. Code C00400, and also the front right outer tie rod is going bad. They wanted $850 for this.

If the problem occurs only when it rains of when wet, you have a problem with the harnesses going to the speed sensors. C0040 is set for the r/f sensor circut. Just because there is a sensor code, does not mean the sensor itself needs replaced. The harnesses are about 70-75.00 each. One way to check (although not fool proof) is to have the car running, in park, and preferably when conditions are set for the light to come on(wet), the turn the steering lock to lock and see if the light comes on. This will flex the harnesses, and if one is broken it will set the light.
Still, at 150.00 (or less) for both sides, thats alot less than 850.00!

You may be able to find the harnesses cheaper online. 70-75.00 is OEM parts.

We called the dealer back. They tested both sensors and individually. When I drove to work this morning it was raining and I turned the wheel lock to lock and it didn't short it. It only seems to happen when I'm going over snow, or there is blowing snow. With the tie rod should I just replace to other side too if my mechanic is going to be right there if that hub is bad?

May as well replace both tie rods. That way you won't be wondering if the other one is getting loose.