2004 XC70 ABS Light - Loose Axle Bolt (Missing) Topic is solved

[tropikchiken]

Hey guys-
2004 XC70 having issues with ABS.

I was driving home the other day, about an hour trip, and in the middle my ABS light suddenly came on. Never seen it before (though I've only had this car for about 5 months).

Other than the light, car was driving normally.

Got home, turned car off and then about 5 minutes later my wife took it to the grocery store. ABS light still on, but now she reported speedometer not working and car was not shifting in auto (but still would in manual).

I read up on the issue and it seemed like a faulty ABS module. I removed module, used a dremel to open it up and made sure all pins had good contact with the board (I think) as this can be an issue. Unfortunately, this doesn't seem to have fixed anything.

Speedometer seems to usually work, but it will cut out occasionally, and then sometimes resume again in the same drive. ABS light is always on, even before driving, and I seem to get a quick traction control warning and feel/hear some sort of noise when first driving the car after it has been off.

Now, I'm ready to order a replacement ABS module from Xemodex, but before I do, is there anything else that could be causing both the ABS and speedometer issues?
I don't want to take it to a mechanic and spend money needlessly if it is 90% chance to just be the ABS module...

Any ideas?

Thanks

[abscate]

You need to get a good scanner or VIDA and read the BCM (brake module) codes

It could be many things and the P2 ABS modules are not known for failing.

Inspect your wheel ABS sensor wiring for breaks first.

[scot850]

+1 to what abscate says, but also check for corrosion on the wiring connectors and possibly on the reluctor rings on the axle ends for rust build up possibly tricking the ABS module to seeing something may be wrong.

Neil.

[tropikchiken]

Thanks for the advice, guys. I visually inspected the ABS sensors and couldn't see anything, and my OBD reader unfortunately won't return BCM codes. I scheduled my local mechanic to take a look on Friday morning and see if anything is wrong.

Perhaps you guys have some insight into the speedometer - not only does it intermittently work, but when it stops working, it's not completely off- it will still register some speed, up to 20mph or so (but sometimes less). Any certain part or sensor that would be likely to cause that kind of issue?

[abscate]

Wheel sensors, any one of them, can do that.

There is no substute here for getting a readout of the BCM code. You can't inspect cars visually or with a VOM anymore.

[tropikchiken]

Just an update - my mechanic found that the CV axle bolt on the front driver's side went missing, and as a result, things shifted out of place and the sensor could no longer get a reading. Once that was corrected, the problem was resolved.

[abscate]

We once cured wcm ABS light with a 1/16 turn tightening of the axle bolt.