Discovery 2 TD5 Auto gearbox

I have a recently bought TD5 2002 which turns out has an auto gearbox problem. The M+S light comes on when I reverse and I have to switch the car off to clear it. Once cleared, the car drove normally. I read it was most likely the XYZ switch, so I ordered a new one from Bearmach. This came and a mechanic friend (who admits he is not a Land Rover specialist) fitted it for me, it now seems to be stuck in limp home mode constantly. My friend said the switch he took off looked in really good order and he suspects has been looked at fairly recently before I bought the car and he also took off the ECU and said there was no sign of water, grease or oil ingress and it looked in really good shape too.
Has anybody experienced the same, or can anybody suggest where to go next? Does anybody know if there is more than one type of XYZ switch for this model, as if the wrong one has been fitted and the previous owner fitted the wrong one perhaps this could be it?

There can be around 18 other reasons than XYZ switch for flashing M+S and limp mode and the only direct way to the issue is to plug in a dedicated tester to read the fault code stored in the transmission ECU's memory... all the rest is a guessing game which has already proved to be expensive without the problem being fixed

Thank you, I think I'm going to have to do that

If you want to understand the automatic transmission system in a Discovery 2 you should down load the rave workshop manual available here d2bc.co.uk which gives a comprehensive description of the system, fault codes etc.
You need any fault codes read by a test book, nanocom or hawkeye, as any other code reader may not give a true reading as the discovery 2 is not obd2 compliant using landrovers own fault code diagnostic system.

If the fault code P705 xyz switch fault is read, be aware that this refers to the xyz switch and associated circuits, not just the xyz switch itself, from the battery through to the electronic automatic transmission ecu.

As far as I know there is only one xyz switch used on the discovery 2 and while the internal working may have changed slightly over the years its function has not.

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Thank you very much for the advice Roy, it’s much appreciated

Had the two green lights come on, granted only a couple of times, and with them low power and no acceleration through the auto box (I thought it was limp home mode, but the lads on the forum told me it wasn't that, thanks again guys for your help). Had a new MAF fitted and EGR removed before a mild tune from 5 Alive, no problems since and running like a Swiss watch at present. Fingers crossed as it's unusual for a Disco to run so well I am told.

Sincere thanks for all the suggestions, I ‘bit the bullet’ and took the car to a Land Rover specialist (Asbbrook in Clyro) who told me that the XYZ switch would almost definitely have been the problem, but when a new switch is fitted it has to be mapped to the car through Land Rover software, £25 and an hour later the car had been sorted and has been problem free now for the last 3 weeks.

BMDL said:

.....when a new switch is fitted it has to be mapped to the car through Land Rover software,

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Now that's some real boll*x sir ... though i'm wondering what they really did for that money to fix your problem

Is it possible that the bcu changed the transmission register from Automatic to manual (not unheard of) and this was the problem all along and all the garage did was change it back, hence the £25 charge, worth asking in case the fault occurs again.

ROY SIMPSON said:

Is it possible that the bcu changed the transmission register from Automatic to manual (not unheard of) and this was the problem all along and all the garage did was change it back, hence the £25 charge, worth asking in case the fault occurs again.

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That's true but what i contradicted was the statement that "when a new switch is fitted it has to be mapped to the car through Land Rover software" which is not true

sierrafery said:

Now that's some real boll*x sir ... though i'm wondering what they really did for that money to fix your problem

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They’re a Land Rover specialist that have been established for over 40 years, they only fix Land Rovers. I don’t know enough about it to say otherwise, however that’s what they told me and I have no reason to doubt them as they didn’t supply or fit the XYZ switch in the first place! They have no reason to mislead me as far as I can see, all I know is that they’ve sorted the problem out and I can’t see the value in telling me it was one thing, when the reality was it was something else? I posted my update in the hope of helping others, not to be told I’m talking bollocks, with respect, perhaps they know more about Land Rovers than you do Sir!

I didnt tell that you are talking boll*x sir i said that those are who told you that "when a new switch is fitted it has to be mapped to the car through Land Rover software" ... and for that i sustain my point that it's boll*x cos that's what it is no matter how long experience they have with Land Rovers... never underestimate an enthusiast who is studying things with passion though... i was trying just to help by that as to not let somebody think that if he replaces the XYZ switch a "LR software" is needed that's all... i didnt want to offend you and if i did i apologise

BMDL said:

They’re a Land Rover specialist that have been established for over 40 years, they only fix Land Rovers. I don’t know enough about it to say otherwise, however that’s what they told me and I have no reason to doubt them as they didn’t supply or fit the XYZ switch in the first place! They have no reason to mislead me as far as I can see, all I know is that they’ve sorted the problem out and I can’t see the value in telling me it was one thing, when the reality was it was something else? I posted my update in the hope of helping others, not to be told I’m talking bollocks, with respect, perhaps they know more about Land Rovers than you do Sir!

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whatever the fault was, you were misinformed over the xyz switch