Brake system failure on 2000 s80

ranson · Post by **ranson** » 31 Jan 2011, 16:19

I have a 2000 Volvo s80 that intermittently the abs, tracs light will come on and the brake system failure stop asap message comes on. When this happens the tach and speedo doesn't work along with the odometer. The abs module has been rebuilt. I was wondering what else could cause this problem. Any help would greatly be appreciated. Thanks

Post by **boosted5cyl** » 31 Jan 2011, 18:42

My experience has been that the first module to throw a fit when the voltages have gotten marginal in my S80 has been the ABS/STC module. Verify your electrics are good. Battery, alternator, grounds, terminals and voltage drop test.

ranson · Post by **ranson** » 31 Jan 2011, 19:07

I have put a new alternator and battery in the car in late Dec

Post by **boosted5cyl** » 01 Feb 2011, 08:35

Even with a replaceed alternator I would still check all of what I mentioned. Assuming that that has been checked, its a weird one. If the tacho wasnt dropping dead too it would probably be a speed or wheel sensor. With the tacho dropping too im not so sure...

Might be an idea to take it to Volvo and get the codes for the ABS module pulled. Again though, without re-verifying the electrics 100% you may end up chasing your own tail.

ranson · Post by **ranson** » 01 Feb 2011, 09:27

Ok thanks for the advice I will check everything out soon

umpernickelnoi · Post by **umpernickelnoi** » 03 Feb 2011, 12:33

Hi,
I have the same problem on my 1999 T6. It spent a lot of (time and money) in Riverside Volvo Hull, where they replaced the ECU, ABS control unit, checked all connections and groundings and installed new software into every module, to no avail.
I found by chance that diconnecting the battery for a few seconds cleared the problem for varying lengths of time, so I fitted a battery isolation switch under the dash so I can stop, switch off engine, swith battery off for a few seconds and restart with everything working again (dash gauges, sat nav etc), this can even be carried out at trafic lights. This car was released before it was fully developed and Volvo are incapable of fixing the problem, they did not even know what were the fault codes it was throwing up. I suggest that you fit an isolator swith and just live with it. Best regards Chris