Right, following on from my SC loosing drive in the field on Saturday I jumped the gun and assumed it was the transfer box causing the problem.

In the TCCM ECU I had a P0915-00 error for Gearshift Position - Circuit range/performance.

In the Vehicle Dynamics ECU I had a U0403 - invalid data received from transfer case control module.

And in the Terrain Response ECU I had faults from the Engine ECU, Transmission ECU, Vehicle Dynamics ECU, Transfer Case ECU and the Ride Level Control Module.

I tested the resistance and functionality of what I could on the transfer box and concluded after testing it on another car that the transfer case ECU had died. Replacing that tonight didn’t solve the problem.

I poked about a bit further using the IID tool tonight and had a look in the Transmission ECU. It shows the Transmission Current Gear as third. The Gear Position Selected shows as Park. This kinda makes sense as the car would have been in around 3rd gear in low range when it packed in.

Click image to enlarge

Click image to enlarge

David,

It's a fatty, it will defy the laws of physics with ease....

We need Guru Phil to decode this mess.....!!!

Rooting for you....  Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Thanks Pete.

Had to happen the week before we're meant to be going away with the caravan for a few days, didn't it!

David. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 5.0 SC Autobiography in Indus Silver with Jet/Ivory Interior
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

Can't you take the devils juice fatty...?? Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

We can do I guess but where’s the fun in that

This fault really is bizarre. The fault code stored in the Transfer Case ECU is for the gearshift position circuit. However there’s no fault in the transmission ECU. When searching ECU’s the transmission ECU communicates and appears to be online.

With the ignition on the car seems to think it’s in 3rd gear regardless of what position the selector is in:



With the engine running the gear shown jumps to 2nd:



The faults will not clear from the car, they return as soon as the ignition is switched on.

Part of me thinks this has to be a fault in the mechatronics unit. There’s someone selling a faulty gearbox from a Discovery 3 in Scotland so I’m tempted to buy that to see if it cures my fault as I believe they’re interchangeable on the pre 2008 cars.

If it does cure my fault then I’m not opposed to buying one but I don’t want to spend 1500 quid on a new mechatronics unit to find my diagnosis was wrong.

David. 2002 4.6 Vogue SE - Alveston Red with Lightstone Leather
2007 Range Rover Supercharged in Java Black with Ivory Leather
2012 Range Rover 5.0 SC Autobiography in Indus Silver with Jet/Ivory Interior
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

PM Phil and ask him before you buy anything...  Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Does the engine run?
Is the gearbox selector cable out of adjustment or disconnected or broken?

Well, after some advice from Patrick at GAP who was incredibly helpful this afternoon he pointed out that the fault code that was logged in the TCCM (Transfer Case Control Module) was referring to the gear selector on the main gearbox.

I checked the cabling and functionality of the selector using the IID tool and it was registering what was expected.

He agreed that it was odd that the selector fault wasn't showing on the transmission ECU but it was on the transfer case ECU. After establishing that the cabling was OK we concluded that there must be something amiss inside the gearbox.

Just as a bit of background, in January I replaced the solenoids, bridge seal, the 4 seals on top of the valve block, and the sump on this box before filling it with genuine ZF Lifeguard 6 that was provided by Rob at Duckworths. This work was carried out on the basis that it had done 130k and prevention is better then cure, not due to a fault. I then reset the adaptions on the gearbox and followed the process for relearning the adaptions along with 5-600 miles of careful driving and the box has performed absolutely perfectly for 2.5k miles...

This evening I dropped the sump off the gearbox and removed the valve body. A miserable job when the car is parked on grass. Makes me realise how much I take the ramp in the workshop for granted!!

Anyway, this is what the new fluid looks like:

Click image to enlarge