So my old 200k+ miles '05 reg 3ltr diesel estate lumbers on but has now thrown what looks like a gearbox problem and now won't select gears. The centre display went bold and diagnostics indicated fault numbers P0729, P0735 and P0783. Initial research suggests either the ECU or the transmission itself - obviously I'm hoping it's the ECU but I can't find conclusive info as to where it is? Some suggest it's under the carpet on the passenger side but is that l/h or r/h drive passenger? I'm going to try to have a look this weekend (if weather allows). I did have a problem a few years ago with the heater matrix leaking coolant into the cab so I'm wondering if the ECU is under the floor whether that might have had some adverse effects, but why has it waited all this time to show itself? Oh, one more clue, my diagnostic box could not communicate with the EMU and that's new so would gearbox ECU failure break the comms chain and cause that too?
Btw P0729 is "Gear 6 Incorrect ratio", P0735 is "Gear 5 Incorrect Ratio" and P0783 is "3-4 Shift".