disco 4 electronics buggered

[petemurphy]

having a mare

have a disco 4. its randomly not starting / letting me in due to haywire electronics. its happening on and off so its not predictable. left it with my local independent for a week and it didnt do the fault once so they couldnt diagnose. now have a car i have no idea if it will start every time i go in it.

indy reckons theres about 10 modules ( or wiring ) it could be but cant trace the fault until its happening.

I do wonder if its related to the large amount of water that came in in the passenger side footwell when sunroof drains were blocked a month or 2 ago.

any ideas how the hell i go about fixing it? would a dealer have any other fancy gadget to trace it or would they just swap out modules one by one and cost a fortune?

thanks

[Bill]

I assume they've tried a new battery??

[anonymous-user]

The Body Control Module (BCM) is above the passenger footwell/under the glovebox. Could the water have run through that area before settling in the footwell?

[A.J.M]

In the passenger footwell area, under the sill kick plate is a one of the wiring harnesses.

On that, in 3 green wires that join together, those control the locking/unlocking.

If they get wet, the locking can screw up. Been there on my D3. It’s an easy fix to cut and solder back together.

For the not starting, it should have thrown up codes.

[camel_landy]

A.J.M said:

For the not starting, it should have thrown up codes.

...or could be that good old brake switch.

If the contacts have corroded, it may mot be detecting your foot on the peddle and therefore not letting you start the engine. If it is, it won't throw an engine code either, as it thinks everything is OK.

M

[petemurphy]

thanks all

do you think battery would be causing random warnings and disabling?

[petemurphy]

F20CN16 said:

The Body Control Module (BCM) is above the passenger footwell/under the glovebox. Could the water have run through that area before settling in the footwell?

quite possibly

[camel_landy]

petemurphy said:

thanks all

do you think battery would be causing random warnings and disabling?

Failing batteries are known to cause all sorts of problems with these cars.

M

[petemurphy]

camel_landy said:

Failing batteries are known to cause all sorts of problems with these cars.

M

so today it wont start at all and does sound like the battery is about gone - cant even emergency start it tries to turnover and dies as if the battery is about dead. guess thats the first thing to try new battery?

[Bill]

I think so. Mine only failed to start once after using a tyre inflator, but threw all sorts of random electrical errors like window switches, suspension etc.

[petemurphy]

replaced battery and all seemed well as i drove off from garage.

10 mins later all the displays went off and random warnings came on. have parked up at home but it wont lock.

least it starts for now with emergency key and new battery.

aaaarrrggghhhhhh

[Bill]

Bugger!

[camel_landy]

Well.... If the main batter is going flat over the period of a few days, then chances are something is preventing the ECU from shutting down properly. Annoyingly, this could be something as simple as the microswitch on the tailgate corroded (making the ECU think someone is trying to open the door).

Your best bet is to try and find someone who can troubleshoot this properly.

M

[s55shh]

could be any of the modules playing up and causing various error messages through the canbus. Expensive game of trial and error coming up

[A.J.M]

Has it been plugged in to have the codes read?

There must be some codes stored in it relating to these issues.

[Deranged Rover]

A.J.M said:

Has it been plugged in to have the codes read?

There must be some codes stored in it relating to these issues.

Don't bank on it. My 2005 L322 Range Rover has been at my local specialist for the last 10 days with some odd electrical problems. A new battery hasn't fixed it and, despite three warning lights on, two warning messages on the LCD and the air suspension lowered to access height and inactive, it's not giving off any error codes!

[davidexige]

petemurphy said:

replaced battery and all seemed well as i drove off from garage.

10 mins later all the displays went off and random warnings came on. have parked up at home but it wont lock.

least it starts for now with emergency key and new battery.

aaaarrrggghhhhhh

I don’t know if it’s necessary or not on the Disco 4, but when I had my the battery changed on my RR sport the Battery monitoring system (BMS) had to be programmed/reset to let it know a new battery had been fitted, I’ve heard this can cause problems with the dash display similar to what you describe if not done.

[Jurgen Schmidt]

Not sure where in the country you are, but I use John Dennis 4x4 in Aylesbury and highly recommend him

[petemurphy]

A.J.M said:

Has it been plugged in to have the codes read?

There must be some codes stored in it relating to these issues.

yes it says theres a fault on the medium voltage circuit ( think thats right - the non essential circuit ) but doesnt say where. ie could be any 1 of 10 modules or the wiring in between none of which can be diagnosed if the error isnt happening at that exact time

he did program the battery. v experienced local lr garage although not a main dealer. would a dealer have any other gadgets to find the fault?

[camel_landy]

petemurphy said:

...would a dealer have any other gadgets to find the fault?

Not sure if they'd have gadgets but they should have the trained staff and access to LR Technical.

M