Rover 800 ABS fault

My K-reg 800 has a problem with the ABS. I thought it suspicious when the light didn't come on at all on the dashboard - when I had a look it had been removed! I replaced the bulb and sure enough, it lit and stayed lit to indicate a fault.

No problem methinks, so I get my multimeter out and test each of the wheel sensors for continuity and voltage when the wheel is turning. No problems there so then I take the cover off the ABS unit itself and there are two relays missing! A quick visit to the scrapyard gets me two of the correct relays and now the light comes on for a few seconds then goes off as you'd expect.

Great - well, not quite. Sometimes when driving along the light will come back on again. Also when I 'test' the ABS it seems to work fine for the first second or two and then the pedal becomes hard and even with more pressure the car doesn't slow down. If I keep my foot on the pedal it eventually skids to a stop with one of the wheels locked. If I take my foot off the pedal but then brake gently the pedal is still "pulsing" as though the ABS is being triggered. After either of the above the ABS light comes on.

Any ideas? I'm guessing that one of the wheel sensors is sending an erratic signal which is confusing the ECU, but could it be the ECU or motor/valve block itself?

Darren

Reply to
Darren Jarvis
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ABS fault code lists

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BBA also do rebuilt modulators but you can buy another 800 for less money & take the old one off.

Reply to
Duncan Wood

Ive not used one but I hear there are split boots available- cut the old one off and join the new around the shaft, glue the seam and clip the ends and jobs a goodun.

No doubt some will tell us how much trouble they have had with split boots :-) but with careful gluing its got to be better than a knackered one and fitted in a fraction of the time of a full one.

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Reply to
Mad Ad

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Darren Jarvis" saying something like:

Please accept our humble apologies for not manning our computers 24/7 on the offchance you might have a problem with your shitheap.

Reply to
Grimly Curmudgeon

I knew somebody wouldn't be able to resist...

Darren

Reply to
Darren Jarvis

Tonight I got around to doing the diagnostics using the ABS warning lamp as mentioned by another poster. It flashed code 39 at me which I looked up and found was the nearside front sensor (though I can never remember which sides 'nearside' and 'offside' equate to). This was puzzling as all the sensors had metered out okay so I took the wheel off...and found that then sensor had been bent well away from the reluctor ring such that there was at least half an inch gap and the sensor tip was aiming at the driveshaft itself not the ring! I removed the sensor from the car and took it to the shed to have a closer look. Sure enough, the metal mounting tag had been bent and the gap between the sensor and the mounting block had been filled with araldite type stuff!?

It's obviously been done deliberately as both of the front ones were the same, though I've no idea why anybody would want to do this. Suffice to say that with all the araldite filling chiselled off, the mounting block filed smooth, and the sensor mounting tag bent straight again, the sensors now sit about a millimetre from the reluctor rings. Even better, the ABS system is now working perfectly - the light goes off after a few seconds just like it should and stays off, and the ABS stops the wheels from locking, without then interfering with normal braking.

So in the end it seems that the ABS system was deliberately nobbled in several places (anybody care to guess why?):

1) ABS warning lamp bulb removed. 2) ABS relays removed (from under plastic cover on modulator) 3) Front wheel sensors bent away from the reluctor rings.

Darren

Reply to
Darren Jarvis

Refers to the pavement. But not on a one way street, obviously.

So the side nearest the pavement is the nearside.

Reply to
Dave Plowman (News)

Man: Nice car, but ABS is shagged (as he just nobbled it) Backstreet dealer: Oh! Man: I'll take it off your hands for a discount (thhnking he will un-knobble it later) Backstreet dealer: No, I can't sell it on now....

And the fault remains for somebody else to fnd... :o(

PDH

Reply to
Paul Hubbard

Perhaps one of those strange people who don't like ABS? And tried several ways to disable it while still being able to get an MOT?

Reply to
Dave Plowman (News)

Common denominator seems to be one of the relays were gone but in an attempt to fix it they gummed the sensors first and found there was more to do to get it through an mot?

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Reply to
Mad Ad

Dunno. It was MOTd in January so I assume the ABS was working then; in which case between January and June somebody's removed the relays and shafted the sensors. I suppose they *could* have bought another 800 with knackered ABS and just nicked the bits from this one before selling it on...

Darren

Reply to
Darren Jarvis

Buy it from someone who knows you ? ;-) Graham

Reply to
Graham

Hmm, I would rather think that the spoofing of the dashboard light was to get through the MOT and that the abs itself was broken before. There's a couple of ways to spoof the system, its a common discussion piece :o

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Reply to
Mad Ad

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