Instrument failure

All,

Any assistance appreciated. 2 weeks ago i had a blowout. Tyre shredded and sheared through the rear ABS cable. Replaced tyre and reconnected cable and all was well.

Today i have an ABS warning light and the front weeks lock up under heavy breaking. In addition i have intermittent loss of the MPG guage and speedo. Ive checked the fuses and the ABS cable to make sure its not arking out but now at a loss.

Cheers and Regards

"523i Touring Auto"

I am assuming you have an E39 5er i.e. the previous model.

If so I had the same fault with the instrument dials which never re-occured after I replaced the battery.  The E39 is prone to weird and wonderful electrical faults which increase in frequency as the battery gets older and less efficent.

When you say re-connected the cable do you mean you have spliced the wires together or replaced the whole wheel sensor unit?  If you have spliced the cables yourself, double check it for shorts.  It is not uncommon for the wire on the car side of the wheel sensor connector to short out, which means replacing the wheel sensor will not cure the fault.

If you have the ABS warning light on your dash you have lost the ABS assistance so yeah your wheels will lock up under heavy braking.

A diagnostic check will confirm what the problem is with the ABS system.

Which rear tyre blew out?  Does the cruise work?  The cruise is controlled by one of the rear wheel sensors.

How are the transmission shifts?  The front wheel sensors provide input to the transmission to determine its shift change points.  Knackered front wheel sensors which cause the ABS/ASC light to come on can also be diagnosed by rough transmission shifts.

HTH

Andrew

Sorry guys, a bit vague with the info.

It was the rear offside tyre, wires were spliced and coated in tape.

Shifting through the box on auto and tip is fine. Car is 99 V Plate e39.

One other thing thats just occoured since my original post is the range meter fluctuates by 20 miles either way at approx 30 second intervals.

Cheers

All,

Finally found the solution to this problem, Apologies if it has been covered elsewhere in the forum but if it helps one person with the same issue then its a winner.

ABS Module was the fault. The bosch 5.7 module is prone to failure and caused all sorts of gremlins.

Random wheel sensor faults (all replaced)

Power fluctuations (who Knows!)

Loss of top wiper speed and speedo

Fluctuating range guage.

Boys to fix it are at http://ecu-testing.com/abs_pump_modules.html 

at £250 its not cheap but i have spent that on diagnostics and sensors twice over.

Cheers