It's a 2008 XC90 AWD, 3.2L with just over 100K miles. It's a vehicle that I sold to my niece about a year ago with no known issues. Lately, it's developed a SEVERE pull to the right when braking. When the vehicle darts towards the ditch the steering wheel lurches to the left and sets the ANTI SKID warning. I sell these Volvos and have for years, I've never seen anything like this. Brake pads and rotors are like new, calipers have all been checked, nothing seems to be sticking. Both front lower control arms have been replaced as well as both front brake hoses and front sway bar links. It's been in for an alignment (for this issue) and the shop can't find anything wrong with it and it lines up perfect. Tires are not wearing unevenly and have plenty of meat on them. Air pressures are all correct. The only known issue is the lower engine torque rod mount is wasted, and I do have one ordered. I can't imagine that is what is causing this issue, but I suppose anything is possible and I thought it was worth mentioning.

Of course, when I test drive it, I REALLY test it. But even driving somewhat normal, it pulls right while steering wheel corrects left and I can usually hear the ABS module activate. It does set a code and that code is BMC U042862 Invalid Data Received from Steering Angle Sensor. SAS has been replace with no change. I'm wondering if the uneven braking is causing the SAS message and I don't actually have a SAS issue.....? I'd prefer not to just throw parts at it, so any thoughts would be greatly appreciated. I've got a nice Autel scanner but can't seem to get it to communicate with the ABS wheel sensors, which is weird because I know I've been able to in the past on other vehicles, so I've got a diagnostic appointment at my local dealer in mid December but would love to figure it out before then!

 

when you say driving somewhat normal it pulls right? is that just driving along or only when braking? What happens when you disable the DSTC ("spin control") feature? see the owners manual how to disable... I'd expect a failed wheel sensor would set a fault code (ABS light/tracs light blinking) so my inclination is that you may have an issue with the ABS valve body not allowing the right amount of pressure to one of the wheel's calipers. This can happen without setting a fault code since the other components like the sensors and the ABS pump would set a code.

 

When I say drive normally, I mean not braking agressively. Problem only occurs when braking, obviously more pronounced when I drive it like I stole it. I agree with everything you said, it sure seems like there is not the right amount of pressure to one or more of the wheels. I had not thought of disabling the DSTC, I will try that. Thank you very much!

 

What brand control arms did you use?

 

Hope you figured this out by now and if so, I hope this info will help others. My '04 did something very similar, but it ended up being the rear rubber brake hose was clogged/swollen in combination with a worn out ABS valve body as described above. VIDA was able to indicate the valve body was not functioning properly and the lack of fluid from the right rear bleeder was an indication of the bad hose. eBay and about $60 did the trick!

 

yep, good tip. Your point is key to the diagnostic process - when a car pulls under braking it means one of two things either the brake caliper for one of the wheels is not actuating or the suspension has issues allowing the wheel's alignment to change. The first thing to determine is the suspect wheel, then physically check for suspension stability and whether the caliper is clamping. If not check if its getting fluid by opening the caliper's bleed valve. No fluid means you need to work back to the source (ie the line at the ABS valve). Fluid yes? time to check the line... Skip a step in the process and you can wind up replacing parts unecessarily.

 

Wanted to follow up on the repair for this issue. Turns out one of the front lower control arms was the culprit. Removed and replaced both front lower control arms and problem solved. Thanks to everyone who made suggestions!