Disco 2 XYZ Switch Auto Box 2004

ES4 said:

Hi Everybody, Well now the cold weather is over I started on the xyz switch only to hit massive problems. can't even hardly see the switch let alone get to it, the cat is in the way. Then I discovered that to get the front pipe off the crossmember has to come off. 8 x 10mm flange bolts. used a brand new hex impact socket got 3 out, the others just rounded off. Tried heat, Irwin bolt removers, impact wrench, nothing will shift them so ridiculously tight. Definitely need some help/suggestions.

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I did mine without dropping the exhaust. Bit fiddly but not too bad once you get yourself in the right position and comfortable. Get the driver's side front wheel lifted up and securely held. Slide under from the driver's side and get some decent LED lights in place. I have one with a long strip of lights and I managed to fix that up towards the back of the gear box. I also tied the exhaust up a fraction to one side and that was enough to reach up to the switch and still see most of it.
I also bought replacement fasteners so I knew which spanners to use, ratchet spanners are invaluable.

For the crossmember bolts (took that off to access the sump) I found centre drive sockets handy (make sure the bolt heads are completely cleaned off) plus some old imperial sockets hammering on one which was fractionally too small and carefully and slowly applying torque with a breaker bar. Try applying some heat and easing oil. Mine all came out cleanly with some patience.

Hi, Thanks for that, was your exhaust the Cat version as I can see no way around it because of the diameter. The bolt heads are well rounded off because I thought the Irwin Sockets would definitely get them out but no. They bit in nicely but because they are so tight they eventually slipped. These bolts have very shallow heads I don't understand why Landrover fit them as there not seen. I think welding a nut onto the rounded bolt and lots of heat is the way forward as has been suggested. I'll struggle on. thanks everybody.

ES4 said:

Hi, Thanks for that, was your exhaust the Cat version as I can see no way around it because of the diameter. The bolt heads are well rounded off because I thought the Irwin Sockets would definitely get them out but no. They bit in nicely but because they are so tight they eventually slipped. These bolts have very shallow heads I don't understand why Landrover fit them as there not seen. I think welding a nut onto the rounded bolt and lots of heat is the way forward as has been suggested. I'll struggle on. thanks everybody.

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Just a big round silencer box which does get in the way. I found it easier to reach round from the front and back of the cat, having gorilla length arms helps.

Hi, Their are 2 types of xyz switches- tan cover with cams and micro switches and a black cover with copper tracks and wipers. Are the interchangeable ? Thanks

Hi, Anybody Know? as above Thanks

ES4 said:

Hi, Their are 2 types of xyz switches- tan cover with cams and micro switches and a black cover with copper tracks and wipers. Are the interchangeable ? Thanks

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ES4 said:

Hi, Anybody Know? as above Thanks

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Yes they are interchangeable as long as they are both for D2 cos there are P38 versions which have different connector

Thanks Sierrafery, Yes Discovery 2. Can I ask does both crossmembers have to come off to remove the front exhaust pipe ( cat version) as I cant get to the Switch. ?

ES4 said:

Thanks Sierrafery, Yes Discovery 2. Can I ask does both crossmembers have to come off to remove the front exhaust pipe ( cat version) as I cant get to the Switch. ?

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Unfortunately i can't answer to that

THE FINAL CHAPTER

Hi, Well eventually its fixed. Mate offered the use of his 4 poster ramp which turned the job around. We didn’t remove the front pipe with cat, instead we only removed the rubber hanger and forced it towards the gearbox and held it over with a ratchet strap. This JUST gave us enough room to get the switch out, which is explained in other posts. What did we find? Well exactly what other people find a burnt degraded contact. But no water ingress. The switch cleaned up really well using isopropanol and the contact cleaned with a glass fibre contact cleaning pen and finally switch cleaner. Dielectric grease applied and M4 bolts refitted. My theory with what causes this switch to fail. The switch is in 2 parts, one side I call the “logic side” and sends the wxyz combinations out to the Ecu’s. The other side only has 2 signals, one is Reverse and the other is Park and Neutral Positions. It was the Reverse Contact that had degraded but NOT enough to prevent the Reversing Lights from working. So why did it cause a P0705 fault code and the sport and manual lights to flash. To be honest I don’t really know but suspect the burnt reverse contact doesn’t provide a clean instantaneous signal to the BCU in time with the reverse signal from the wxyz side of the switch or maybe very small contamination from copper wear mixed in with the grease corrupts the wxyz side as well. How to prevent this from reoccurring in the future. Been an Electrician the reverse contact looks like it is under rated to carry the load current of the reverse lights (3.5 amps) all other contacts probably only carry Mamps. Also every time you move from Park to Drive this contact makes and breaks that load in both directions. There is no relay in the Reverse light circuit to carry the Load. Modifications to try- Fit a relay or better (easier) still fit LED bulbs as this reduces the current to 1 amp a 2.5 amp decrease of load on the reverse contact. Take care everyone.