2004 Volvo XC70 Automatic ...

About a month ago, I bought this vehicle and replaced the right-front cv shaft and hub/wheel bearing assemblies. About a week (and perhaps 400 miles) later, I was getting the ABS light, the little orange triangle with an exclamation point in the middle, and a message about ABS and anti-skid system. I don’t remember the exact verbiage of the message, as I don’t have the car with me at the moment. I also noticed some pulsing and grabbing of the brakes at low speeds, especially when coming to a stop. The AWD system would also come on and off, mostly during hard turns at low speed. I pulled the wheel and found the center axle bolt had backed completely out. Either I did not torque it at all or did not torque it enough. I torqued it down nice and tight with some thread locker, and cleaned a small amount of soot and grease from the sensor. I reassembled it and the symptoms went away. All was good the dash had no warnings...

A week later, the same exact symptoms showed up. I pulled the wheel again. This time, I double checked that the bolt was tight, which it was. I tightened it a little more for good measure. I pulled the sensor again and blew out everything in and even remotely around the hub with compressed air until no more dust came away. I then sprayed some brake cleaner down into the sensor hole while rotating the hub to make sure the nibs that the sensor are supposed to see were squeaky clean. I reassembled and all the issues went away.

Another week later, the same symptoms came right back. This time I made sure to get a brand new axle bolt from Volvo (p/n 30640878) and torqued it to spec, 35Nm plus 90 degrees. I did not pull the wheel or the sensor this time. I drove the car and everything went away again, but only for about fifteen minutes before the symptoms reappeared, same AWD thing coming up, same occasional grab/pulse of the breaks when coming to a stop, same lights and the same warning on the dashboard.

Besides having a weekly ritual of wiping down the sensor, does anyone have any ideas on what I can do here? I am out of ideas ...

 

You are going to have to get a scan tool that can stream live data while someone else drives the car. It appears that you are getting a false signal that is confusing the tracs system.

Other than using the parts cannon and just tossing parts around, you have to get a diagnosis.

 

Yeah, I was afraid of this. I wonder if it is just a scanner or if I need some sort of laptop/tablet software sort of thing ...

 

Why is everyone always "afraid" of the most simple things? Have a mechanic with a scan tool do a diagnosis. It will probably be the best $100 you spend. You've already experimented with solutions without a diagnosis.

 

Is the axle aftermarket?

 

Did you ever figure out what the issue was?