ABS light on? This is more than likely the problem.

[dralphs]

John

some extra info i have regarding speedo and abs

regards

dave

[Gnomy]

Thanks a million dralphs.............

Volvo has had my car for over a week and they can't find what's wrong with it. Not sure if it's a seriously strange issue or maybe the local (South Africa)Volvo guys aren't clued up enough.

I'm planning on flushing the braking system (as per suggestions in this forum) and, now armed with these signal levels, checking the ABS ECU. Loom under the radiator/battery looks fine. I'll post my findings when I've had a chance to do it.

[Vash]

Guys what reader will give ABS codes?

I have now got so sick of this problem that my T4 is back at a garage to fix but they only have a posh expensive snap-on reader and it wont give them the ABS codes, even though it should in their minds.

So they are now well ****ed off and I am now even more ****ed off.

[phillwoods]

Volvo told me that i needed a new ABS unit at a cost of £970 (part only). I bought one from a breakers in London which didn't turn the light out. The company replaced this with another one which still didn't seem to work! Turns out Volvo misdiagnosed the problem and ended up being a wire under the radiator!
Volvo fixed it for free but i now have an ABS unit going spare that i paid £110 for!

Does anyone need one?

Cheers

Phill

[NorfolknGood]

I have done no more to my Vulva and the problem 95% of the time is not there any longer. yesterday I fired her up and the ABS light was on, drove down the road 100 yards, switched off ignition and back on again (whilst still moving forward) and no ABS light it stayed off not been back on since. I have no idea why the problem appears to be curing itself but I'm not knocking it.

I have named my Vulva "The Virgin" as it's behaving like a perfect ***t

[Kishada]

I've just been through this problem and found exactly the same problem with the power wire as identified in the first post.
My symptoms were: ABS and the red exclamation light intermittently coming on over a week or two, then staying permanently illuminated.

Here's a couple of codes to look for as an indicator that it's a wiring problem. Only one of these may be present, and these were recovered using a Bosch KTS at my work.

000F = Valve relay faulty
0010 = Pump motor/Engine relay faulty

There is NO abs pump relay present in the fuseboxes. I confirmed this with Autodata. Therefore the relay if present is contained within the pump ecu, but irrespective of this it indicates a LOSS OF POWER at the pump. Using the Bosch KTS to look at livedata, with the engine running, the abs "relay" was showing as open ie not providing power.

It seems that about 50% of the time the abs pump is at fault when people have this problem (without scanning for codes!), and i changed the pump first (i hate wiring problems!). My logic for this was that one of my codes read as Solenoid Valve 4 was faulty which i thought could only be a pump issue. However, this caused me considerably more problems in terms of one of the front brake caliper bleed nipples snapping and the other rounding. Even more problems with one of the front flexi hose banjo ends rupturing when trying to bleed through the banjo bolt. Moral of the story being check that all 4 caliper bleed nipples crack free before you touch the pump! My 2 lights were still on after replacing the pump and two front brake calipers. Demoralising and wallet busting to say the least.

It seems that the other 50% of the time, the power wire is at fault in exactly the same place as outlined in the start of this thread. I ended up leaving my battery in and taking the radiator out. Just to clarify for those that are looking at the wiring, it's at the pasenger side just after the loom makes its 90 degree bend from vertical and starts to run along the inside of the front lower radiator support (horizontally). I unwrapped most of the loom before i found it, not knowing exactly where to look. Only a small amount of wire needed to be chopped out of the existing loom (about 2-3") and i used the screw in the barrel terminal strip style connectors to join it in. My soldering iron was not capable of heating cable that thick. I think it was 27A cable that was the same thickness as the standard loom.

My wiring loom was slightly damp in that area and one possible cause is that just above this area in the vertical section of the loom, there is a split in the conduit that would have allowed the ingress of water and it would have collected in this area. My radiator is also starting to weep along the lower tank seam.....

Hope this helps some of you.

[Jimmi V40]

Hi all

I am a 'Johnny come very lately' to this thread so hopefully someone may be able to answer possibly I don't know!

I have read through many of these posts regarding ABS and none of them seem to happen in the same way.

By that I mean my ABS light randomly only EVER switches on at the same time every time, and that is when I hit 50 mph after about 10 secs. If I don't go that fast, I can drive for days without it switching on, but once it is on, it will stay on until I switch the car off. Then, it won't turn on again until I get to 50mph.

It only started happening after my local garage replaced the hand brake after it failed it's MOT (road test in UK). I took it back and they claimed to have fixed it. They hadn't and when I went back after using it again for the first time at 50 mph they had closed!

Any advice from anybody??

Thanks, Jimmi.

[s40t4suff]

http://www.matthewsvolvosite.com/for...hp?f=1&t=12651

[Montego]

I too have just diagnosed an open circuit +12V feed wire to the ABS relays.
It was corroded in exactly the same place as others have found. I believe that the reason for the failure is that the cable is under-rated for the current it has to carry. This causes overheating of the wire which repeatedly swells the outer covering, which then shrinks back when the car cools down. This repeated heating/cooling cycle results in the wire covering become "crinkled" along its length where it is contained in the loom (which prevents the heat from readily escaping). Eventually the covering splits and allows the elements(water!) to take their toll. The reason why the failure happens at the point it does is because it is close to the radiator bottom hose which provides a local hot spot.
But why does it get so overheated when the ABS is hardly ever called upon by normal driving? The 2 relays inside the Bosch ABS unit both have to operate for any significant current to be drawn(to power the pump motor). The one time that the system regularly draws full current through the 2 relays is when the car is started, when the ABS system goes through a check routine. Perhaps it could be this continuous cycle that eventually causes the problem. It would be most likely to cause cable failure whenever the engine is re-started from warm when the vehicle has been stationary for a while and the radiator/bottom hose has warmed the cable loom to the point where the plastic cable cover has softened. This could be particularly acute on hot days.
Thanks to those who have taken the trouble to air their findings about this very unusual problem. Volvo owners are special!