02 V70 XCAWD Low Voltage Message - Now Dead
 

Had power steering pump replaced last week (88,000 miles) and after a few days my wife reported a Low Voltage message upon start-up, but then it went away and all was fine until tonight. I was driving and I felt two light thuds/clicks that seemed to occur as I began braking, seemed to come from under brake pedal. The Low Voltage message came on so I pulled into the nearest AutoParts store. We tested the battery at the battery and it passed (rookie mistake - didn't get the reading from him), then we tested the alternator up front at 2K RPM and it passed (rookie mistake again, no readings).

Shortly after he disconnects the clips, I start to get random alerts, ABS light, thenthe Low Voltage message. I tried driving home, and noticed the dash lights were dimming, then "Brake Failure, Stop Safely" message. I am less than 1/2 mile from my home so I decided to try and limp in. Accelerationwas nearly dead, andshefinally shut down half-way up my driveway. Couldn't restart even with a different set of keys or after waiting 30 minutes.

I recently learned this car has computerized throttle control (no accelerator cable from pedal to motor, but computer senses foot action and relays message to throttle). Are the brakes managed the same way?

Does anyoneknow ifall of these symptoms point to original battery being low or some common electronic part? Or am I in for a BIG $urprise?

RE: 02 V70 XCAWD Low Voltage Message - Now Dead
 

Just heard back from my mechanic... suggesting I replace the regulator component on the alternator and if that does not do the job, then replace the whole alternator. Price difference between the two is about $200.

Anyone have any thoughts on this diagnosis and recommendation?

Thanks!

RE: 02 V70 XCAWD Low Voltage Message - Now Dead
 

Check a small wire from the alternator and see if it is pulg in or not. or hanging around alternator or compressor area. At time even i forget to plug it back in when I replace a power steering pump. also check the big cable on alternator for tightness (CAUTION DISCONNECT BATTERY "NEGATIVE" CABLE BEFORE U CHECK FOR TIGHTNESS ON THE BIG RED BATTERY CABLE AT THE ALTERNATOR) also check Battery cable at the battery. hope that helps

RE: 02 V70 XCAWD Low Voltage Message - Now Dead
 

Thanks for the suggestion. I had the regulator module on the alternator replaced and stayed with the original alternator. So far, so good. I'll keep my eyes and ears open for any electronic oddness and reply to the thread if anything comes up.

Regulator component
 

Out of curiosity, how do you check the regulator component? I've got a '99 with very similar issues. When fully charged, runs fine, if I remove the + battery cable, car dies which tells me alternator is not generating charge. I was planning on replacing the alternator, but if I don't have to.........

Thanks in advance.

Al T

Check voltage at the Alt red wire with the car running it should be like 14.25 volts or close to that.

It has now been quite some time since this post and I am extremely curious to know if the regulator module was indeed the solution to your problem. My XC70 gave the same problems this week-end and a brand new battery has not solved the Low Voltage warning (and sluggish performance).

In the General Forum thread (not sure that's the exact name, but you'll find it) there's a sticky from a contributor who detailed all the problems he had and solved with a new regulator. And an explanation as to why this occurs. Its pretty interesting, and very thorough.

In case it helps someone in the future, the new regulator module installed in November 2007 seemed to do the trick. It has been three years and about 30K miles without any problems.

I've got a new problem, which is probably due to age, that looks like time for a new belt and alternator.