Disco TD5 Auto electrical issues

you have PM

Right back at ya......

About what you told me regarding the XYZ switch(to keep it public maybe others will have the same issues) ... the outputs/feeds of XYZ switch are all passing through the BCU which comunicates with the instrument pack

RAVE said:

The cover incorporates lever position indicators and the mode switch. The lever position indicators illuminate to show
the position of the selector lever. Illumination is controlled by the Body Control Unit (BCU). The mode switch is a non-latching
hinged switch that, when pressed, connects an earth to the EAT ECU to request a change of mode.

Click to expand...

though a dodgy reverse signal from the switch would disturb things... but as long as the reverse lights are working you'll end up at the BCU again ...reverse lamps are direct from the switch not through the BCU like the wiper, if the reverse lights are making tricks aswell then the switch is the suspect

...and other thing which leads to the BCU or to the comunication link between the BCU and IDM(and the fact that you lose connection with the BCU when the fault occures)

RAVE said:

All functions are disabled on power up until communications between the BCU and IDM have been established. If
communications cannot be established, operation will commence with degraded functionality.

Click to expand...

if you want to DIY open RAVE -Workshop manual-Body controll unit-Description and operation and start reading

Yes, I think I understand the interfaces you are referring to.....The reverse lamps work fine and illuminate when reverse is selected. The gearbox ECU and the engine ECU are getting the correct signals, as confirmed by Nanocom and the gears are changing as they should. I've also been considering the IDM as a possible culprit as the issues only happen when I start the engine. I've had the IDM out and inspected it visually and it was perfect but there could be something amiss within the processors or something like that.....I will try and get a passenger compartment fusebox and swap out and see what happens. Ater that, it's off to the gearbox loom to check there.....

Once again, great help sierrafery and is as always appreciated.

Hi all.....Just wanted to update. Problems all solved now. Eventually got hold of a lower mileage BCU with a different part number. Fitted it this morning. All electric gremlins disappeared. Once I wrote all the settings from the original BCU and Requested the ECM to learn the security code, she fired up and all systems functioning properly now. Thanks everyone for the inputs.....