Disco 2 2001 Disco TD5(manual). ABS, ETC, descent, and brake lamps ON

Please may I have some advice regarding the activation of the ABS warning lamp, in particular what circumstances cause the lamp to be switched on. Threads here seem to be dominated by the 'three amigos', but this isn't that.
A friend's ABS light illuminated about a week ago. The lamp is persistant, in that it does not reset each time the ignition is cycled, so I believe it to be a genuine and correct reaction to an erroneous condition.
I assume there are a limited number of single fault conditions that will cause this lamp to be lit?
1. What are these conditions?
2. If I correct the fault, will the lamp be extinguished?
3. Where can I find more information on this system, ie what are its main components and how do they interact?

Regards, MM

Hi, some things have to be clear before a more complex answer:
1. Do the other ABS related warnigs(HDC, TC) lighting up on ignition self test?
2. The ABS warning stays on even if the vehicle exceeds 10mph?
about your questions:
1. there is no fault in the diagnostic protocol which brings up the ABS lamp alone.
2. if any ABS fault was eliminated the warnings shluld go out, the code will stay logged in the ECU memory as hystorical untill it's cleared
3. if you want to study the system you can find all the informations in RAVE,
download disc 1 from here : http://www.myrangerover.co.uk/rave-workshop-manual/ and see Worksop manual - Brakes - Description and operation, a ''flavour" from it

Thank you again @sierrafery

It seems I do have RAVE, because I was looking at the very same page at 3am this morning!
It was reported tome that the ABS lamp came on whilst driving, not sure of the exact circumstances but I will get access to this Disco today to clarify.
If I understand it correctly there is a connector C0505 on the Self Leveling Anti-lock Braking System (SLABS) ECU, from that connector I can measure the resistances of each of the 4 ABS sensors, the values of which I remember reading last night...just can't remember the value itself! I'll look again.
I note also the possibility that the original fault may be classified as permanent, and if that's the case I'll need a code reader to extinguish the lamp(s) once fixed.

WOW, these Landies are very sophisticated beasts - no wonder those Geeermans bought Rover, to rape and pillage the 4x4 technology.

1 edit to correct connector number

This happened the same on a friend's D2 V8 though.
He fiddled around with the wiring at the fuse box in the engine bay and swapped the ABS relay. That fixed the ABS light from staying on.

Update, it seems I was misled by the operator (owner) initially. He failed to report that all 4 of the warning lamps are illuminated, and the table on page 70-23 seems to suggest 9 possibles out of the 11 listed faults...geez, with 4 lamps surely LR could have improved their diagnostic information.
Ah yes, 'refer to Testbook'.
I'm on the case, going to get my hands dirty, I'll report back later today...

Update as promised.

Today I removed and inspected the ABS modulator switches, and the associated connection flange bolted very tightly to the side of the modulator.
Temporarily reconnected, I measured the resistance between the connector pins (where the yellow&green and black wires go?). I got 3 kohm with no switch operated, 2 kohm when either switch was pressed, and 1 kohm when both were pressed. Textbook readings, and I'm satisfied with that. All was reassembled but....there is a quiet regular high pitched buzzing coming from the ABS modulator, at about a 2 Hz frequency and about a 25% duty cycle, with the ignition off and the key out. I didn't hear it when I started, but then I wasn't listening for it...is that normal? Is it indicative of some other problem?

The next thing I did was measure the resistance to each of the four ABS wheel sensors, measured from the pins of the plug C0505 under the glovebox. Three of the four sensors read around 880 ohm each, with the left rear one up at 1040 ohm...within tolerance, but is this a cause for concern?

Finally I went for a short drive to test the results of my actions. No change to the lights, all four warning lamps on (ABS, brake, hill decent, and traction control), but then again no additional problems created!
Here endeth my first encounter with a Disco.
It's booked into the Landy dealer Thursday, when they are going to read the DTCs and determine what to do. Would it be reasonable to ask them to clear the codes? In this way I can see if the problem recurs, and also whether the work I have done has in any way repaired the car.

Final point: I read that the ABS system uses a reference earth somewhere, and if the self check sees that this has failed it will show the warning lamps as described. It seems reasonable to check this earth point for corrosion or failure in some other way, but where is the earth connection located?

MM

The reference earth is one of the two in front of the airbox... that buzzing noise is worrying and makes the ECU suspect... Meanwhile see this post https://www.landyzone.co.uk/land-rover/power-issue-it-never-ends.341579/#post-4472480 maybe you find somebody close with nanocom to help and tell us the fault code(s) cos main dealers have no more experience with older vehicles so you might be confused by them and pay big money just for a diagnose

Thanks for all your replies and suggestions.
Owner of Disco II took it to garage on Thursday. He asked them to read the codes and note them, then clear them.

Eventually this was done, and the diagnosis was that the rear left ABS sensor was duff. Interesting that the resistance reading from that same one was different to the rest, but well within the Landy tolerance given in RAVE. (It was 1040 ohm, the others around 980 ohm each)

He's going to let them change that single sensor (at whatever cost, and that's nowt to do with me, though he reports garage claim 2.5 hours labour to change sensor).

Interesting to note that 48 hours later those pesky 3 (4?) Amigos have yet to return. I half suspect it's a poor electrical connection where the sensor joins the loom, but
1. I'm not going to get the chance to check this before the garage do the job, and
2. If I did, and a month later the lights returned, I'd get no thanks!

Interesting note 2, I see that Bearmach have sensors for about £270, EBAY sellers less than £20 !!! Does anyone have experience of the difference between the two? The price difference suggests a lot!

MM

Update:
Landy garage (not to be named yet, to give them a chance to redeem) charged mate over £400 to 'change ABS sensor - rear left'....but didn't. An hour after leaving the premises those pesky 3 Amigos were back. A cursory inspection revealed that the sensor had not been changed. Mate naturally returned to garage to remonstrate, and their response (a cunning and clever response) was to claim innocence on the basis that 'the workshop didn't tell us they hadn't done it'...the workshop mechanic said 'I told the apprentice to tell reception that we ran out of time.' What (well rehearsed) crap!

Anyhow (foolish) mate has booked Disco back to have the job done...I am sure they'll find 'something else' to charge him for to help pay for their loss of fraudulent earnings, can't help having those cynical thoughts.

End of update..

Hmmmm..... don't know the Disco at all, but my P38 ABS sensor took me 40 minutes to change from parking up to driving off again and included jacking the car up and removing/replacing the wheel.
The "new" sensor was a modest <£20 price I think. Job-Jobbed. No more TC or ABS lights.

Hi, With the D2 the usual cause of the amigos is the wheel bearing on the way out. This causes mis-readings on the ABS system and puts the lights on.
Griff

The cynical voice in my head was spot-on.
Garage now say they didn't change the ABS sensor because they found that the hub bearings were 'shot'...so they are going to charge him 'a bit more' for the hub.
Work should be finished tonight.
Oooh, I can't wait for the next instalment.