Discovery 4 electrics turn off while driving

[Steve86]

Hi All,

So we managed to get a month into disco ownership before an issue came up.

While driving we have a number of items intermittantly turning off & on including temp gauge, air con, central display unit, parking sensors, indicator display. Fortunately there's no mechanical shut-offs & speedo, lights, indicators (external) etc continue to operate. No warning messages until the car is switched off & a whole bunch flash up. It clears when the car starts up again.

Very similar issue reporting in this thread:
2012 LR4, electrical issue. Dash go blank while driving. - Land Rover Forums - Land Rover Enthusiast Forum

Quote from thread:

So take your pick on what fixed mine:
1. New alternator, which was badly needed anyway
2. New BMS, which was also reset a few times
3. Refurbished instruments, but they had other issues anyway
4. New battery, the new battery I previously fitted was not holding charge properly, but that could have been caused by the electrical issues as I was getting some strange charging behaviour
The problems still persisted and became more frequent until:
5. I played with the wiring in the centre console ( lots of large connectors carrying the HS and MS can bus there and most of my faults related to the MS canbus)
One more instance of the faults, then nothing since.

Personally I suspect a dirty connector. It would work intermittently when there was enough charge to jump the connection, but would fail when the charge dropped ( which the BMS dictates when the battery is fully charged, or under acceleration) ?


I'm assuming the same issue as suspected in their thread - loose connection. Has anyone else had this issue?


Cheers,
Steve

[Eric SDV6SE]

There are a number of earth points on the car, any one of them can cause gremlins if a poor connection. Sounds like the new alt and battery have sorted most of your issues, but still check your earth's and major connectors, use a good contact cleaner. I note that a failed/ing alternator can quickly destroy a new battery, so always a good starting point.

[drivesafe]

There are a number of earth points on the car, any one of them can cause gremlins if a poor connection. Sounds like the new alt and battery have sorted most of your issues, but still check your earth's and major connectors, use a good contact cleaner. I note that a failed/ing alternator can quickly destroy a new battery, so always a good starting point.

Hi Steve and as Eric posted, check all your connection but pay particular attention to the earth cable from the motor to the body.

There is a common problem where this cable's connection to the body, can rust.

If so, you will need to remove the cable, clean rust and cold gal the area.

[Steve86]

There are a number of earth points on the car, any one of them can cause gremlins if a poor connection. Sounds like the new alt and battery have sorted most of your issues, but still check your earth's and major connectors, use a good contact cleaner. I note that a failed/ing alternator can quickly destroy a new battery, so always a good starting point.

Hi Steve and as Eric posted, check all your connection but pay particular attention to the earth cable from the motor to the body.

There is a common problem where this cable's connection to the body, can rust.

If so, you will need to remove the cable, clean rust and cold gal the area.

Thanks for responses. Should have made clearer that the list of actions included in original post were done by another owner with similar issue to mine.

After a couple of short runs with no issue we decided to drive an hour across Perth on Xmas eve. Car ran fine on the way up but we had the fun of no air-con on the trip back the next day (only 42 degrees!). It seems that this intermittent fault occurs more frequently when the car has not been driven for 24 hours, alternator/battery issue may be potential cause but as it's only been occurring for a few days is hard to say.

Are the earthing cables under the bonnet or run through the frame? Had a look yesterday & I think the two pics below show the battery & engine earth cables (I'm in no way mechanically competent). From what I can see the connections look ok.

We're already booked in for a service in a couple of weeks, but if anyone knows a LR electrics specialist in Perth I'd appreciate contact details if it stumps my mechanic.


D4 Cable 1.jpg

D4 Cable 2.jpg

Cheers,
Steve

[Eric SDV6SE]

2nd photo is correct, I believe there is an identical one on the opposite side of the engine bay. First photo not so clear, all I can tell is the battery terminal.

[josh.huber]

Thanks for responses. Should have made clearer that the list of actions included in original post were done by another owner with similar issue to mine.

After a couple of short runs with no issue we decided to drive an hour across Perth on Xmas eve. Car ran fine on the way up but we had the fun of no air-con on the trip back the next day (only 42 degrees!). It seems that this intermittent fault occurs more frequently when the car has not been driven for 24 hours, alternator/battery issue may be potential cause but as it's only been occurring for a few days is hard to say.

Are the earthing cables under the bonnet or run through the frame? Had a look yesterday & I think the two pics below show the battery & engine earth cables (I'm in no way mechanically competent). From what I can see the connections look ok.

We're already booked in for a service in a couple of weeks, but if anyone knows a LR electrics specialist in Perth I'd appreciate contact details if it stumps my mechanic.


D4 Cable 1.jpg

D4 Cable 2.jpg

Cheers,
Steve

Steve in the first photo the negative post looks like it's in the wrong spot, like it's broken, plus is there an extra earth wire on it? The orientation of the terminals post looks weird

[drivesafe]

Your motor to body earth cable is located down in the back of you wheel arch.

The first photo is your cranking battery negative terminal and that THICK cable bolts to the arch next to the inner guard, behind the fuse box.

The two studs in the second photo are earth points for electrics.

SPECIAL NOTE, the nuts on those studs once removed and then rescued, can work loose. I replace those nuts and all similar nuts with nylock lock nuts.

Those Land Rover nuts are a one-time-use nut and if you have to remove them, throw them away and replace with lock nuts.

[Steve86]

Steve in the first photo the negative post looks like it's in the wrong spot, like it's broken, plus is there an extra earth wire on it? The orientation of the terminals post looks weird

Will have to go through service history to see when battery was last worked on but it'd be odd if this was the cause of issue that's only just started to happen. By extra earth wire you're referring to the thinner wire?

I'll put up a better photo showing the battery in a couple of days. Would be good to compare it to a standard setup.

Your motor to body earth cable is located down in the back of you wheel arch.

The first photo is your cranking battery negative terminal and that THICK cable bolts to the arch next to the inner guard, behind the fuse box.

The two studs in the second photo are earth points for electrics.

SPECIAL NOTE, the nuts on those studs once removed and then rescued, can work loose. I replace those nuts and all similar nuts with nylock lock nuts.

Those Land Rover nuts are a one-time-use nut and if you have to remove them, throw them away and replace with lock nuts.

The thick cable is an earthing cable then? Was hard to tell as there's not much space to look behind fuse box.

Good to know nuts are one-use only

2nd photo is correct, I believe there is an identical one on the opposite side of the engine bay. First photo not so clear, all I can tell is the battery terminal.

Thanks, I'll have to check the RH side when I get home in a couple of days.

[DazzaTD5]

Over the years I've had odd continuity issues with mostly D4 models but have managed to fix them.
A good percentage of these had continuity issues between a plug and a module such as the abs.

Oddly enough or not but mobile cranes and mobile elevated work platform were extremely prone to this sort of failure, constantly.

I've had one particular customers D4 that after each time I "fixed" it, it would perform faultless (i think even for months) and then suddenly fault again.
Thankfully it never took a dump while they were in a remote part of the country.

It is now with the auto electricians I have used for many years and hopefully they find the fault as there is no way I am simply going to shoot the parts cannon at it until either its sorted or the customer is broke. That to me in an unacceptable (but oh so common) method of repair.

[shack]

is no way I am simply going to shoot the parts cannon at it until either its sorted or the customer is broke.

Parts Cannon.... Beautiful