3 Amigos and then some!

Before you say....... 'Do a search, its all been done to death', Here is a (maybe) new slant on the subject.

D2 V8, '02 started the classic symptoms a year ago, intermittent warning lights, going off when ignition turned off, staying ok for maybe a few weeks, maybe a few days. Worse in wet weather.
Test book gave a faulty sensor, duly changed. Problem continued.
Eventually, lights went permanent on. I still had ABS operating, but no traction control.
Had the faults cleared via testbook, drove away from the dealer to see if new fault showed, but soon as I reached 20mph the nearside front brake went into Hill descent braking, ie pulsing on and off rapidly. To get mobile, I removed the ABS relay which did the trick. drove back to dealer, test book gave no fault other than open circuit from removing the (replaced) relay. To be sure, we cleared the (no) faults and tried again. Same result - brake pulsing again. Also, rear air suspension light lit up and jacked up back end! Couldn't stop it on the switch either.
Removed the relay, drove at 30mph, suspension dropped, and was ok after.
Back to test book - now showing rear offside wheel sensor fault. Replacing the ABS relay restored the brakes to normal operation, but as soon as it goes on Test book, it brings the pulsed braking back on that same front wheel.

At the same time, the engine warning light has been on for a few months, showing Maf sensor fault. reset it several times, all on genuine testbook, still faulting, so put in a new Maf -£150. a mile later, light is on agin! Test book shows maf fault.

Both me and the mechanics are baffled - the ABS faults seem random enough that we suspect the ecu is playing the pratt, but a £300 for a new one, on a suspiscion only!!!

Any one got any ideas? Also, can I fit a secondhand slabs ecu ? - the dealer thinks only new ones can be used because they have to be burned in to each individual vehicle with testbook, but he's not sure.

Incidentaly, in the middle of all this, I did the ABS pump wiring bypass that is supposed to cure the 3 amigos, but no change there!!

Thanks for that Airhook - will give Boys club a look. You suspect the BCU rather than the SLABS unit, which puzzles me, but as all the units are in the same place, I will be looking at both items while I'm under there!

airhook might have a point there cos the HDC relay is integral part of the fusebox

but did u put a new relay instead of the one u removed?
cos http://www.landroverclubvi.com/uploads/2/3/9/8/2398536/abs_relay_contacts_sticking_sec.pdf

and

1. IMO, something connected to the SLABS ECU is at fault for the breaking issue...u can use second hand unit(as long as u are certain it's faultless)... the ABS will work by default and for the SLS part u'll have to plug it in and set the ride height(sensor recalibration), that's all... there are some risks though as always, the biggest is that if u have some strange wiring issue it might disturb/ruin the other ECU too(let's hope u are not as unlucky)... if u can handle a multimeter i can explain u how to check the wiring but it's a big job cos u have to reach hidden connectors to make continuity checks untill all the ECU's plugs, first u must check the sensor wiring which is not complicated... u have to use an ohmeter at the ECU's plug and check resistance on each sensor's input... there must be between 950-1100 ohm ....check first for corrosion/water ingress there, second hand SLABS units are not that bad, the ebay is full of them around £45

2. For MAF the wiring damage is quite common but not as bad to check, see this http://www.landyzone.co.uk/lz/1950398-post6.html



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Thanks to you also sierraferry - Looks like many happy hours with multimeter are about to begin! I may well take up you offer of a wiring check talkthrough, but will check corrosions points first.

Cheers,
Pete

BTW, no, same relay refitted. I notice that it was very hot when I removed it... but its very hot under the whole bonnet, so didn't worry too much. Too hot to hold though.

Well, took out the SLABS ECU, checked all the pins and sockets, no signs of water, no corrosion. Great. Put it all back together, then noticed the rear suspension has dropped. Started up - Horrors - NO LIFT. Presumably, removing the ACE ECU to get to the SLABS has annoyed the wretched thing, and its having its revenge. Any ideas what will make it sit up again anybody? No doubt, it will involve Testbook, which is unavailable to me at present.

Oops - red faces all round! The old 'Open door' trick caught me nicely! Shut the door, up goes the arseend. Phew!