P0A1A-87

[veebs]

So my alternator died, and on the way home from getting it replaced I got the same Charging System Fault that brought me to the workshop in the first place. Key difference, now the system is dumping 15v into the car vs the previous 12v

IID showed the original fault was still listed (ie, from before changing out alternators) and clearing wasn't working.

I did a hard reset, only to be immediately greeted with the same dash error.

IID now reveals the above error code, Generator Control Module, Bus signal/message, missing a message.

Has anyone encountered this?

The Indy had a bit of trouble getting it out (took 3 days), eventually doing what I had previously read about, and loosening the starter motor end on the cable to get enough length. My own suspicion is the sparky hadn't done this too often, and so may have missed or bumped something in the repair process?

It's going back on Monday, but would be keen to hear any ideas from this knowledgable forum!

[DiscoJeffster]

Broke the sensor wire that drives the alternator output. It’s a bitch to undo and probably got damaged. It’s a single wire into a plug in the side of the alternator.
(Or he didn’t reconnect it?)

[veebs]

Well ****.

I'm guessing that means completely disassembling again?

[DiscoJeffster]

Well ****.

I'm guessing that means completely disassembling again?

If it’s the issue then yes it will be. Can’t see how that’s not it.

[DazzaTD5]

The D4 3.0lt is just that little bit harder to do over a D3 2.7lt (yes believe it or not Land Rover made another job harder to do).

The signal wire on a D4 ends up on the positive side of battery and looks like its some little wire thats been added for something, I would make sure its still connected, I have seen them broken or simply left off for some reason.

[veebs]

Current suspicion is that the solder in the signal wire plug at the alternator has been weakened by the previous alternator heat, and now no longer making adequate contact to prevent faults.

Sitting at the workshop for another day or two - breaking the sparky's heart I think.

[veebs]

Update: All the cables have been checked and continuity confirmed, bench tested the alternator and all is OK there, but the problem remains... The old alternator was also tested, with all manor of crap falling out of it - confirmed dead.

Suspicion (fear) now, is that the computer may be fried due to a voltage spike. Currently putting the car back together before shipping off to the electronics guru.

Has anyone heard of this before?

[veebs]

All fixed...

In the end, after removing and re-installing the alternator, re-checking continuity of everything, scanning the various ECUs, the eventual fix involved bringing the car back to 'Newborn' state. Something the guys at the garage had never seen before, certainly not in a Disco 4 (their words)

So, for future readers with a seemingly unsolvable charging system fault - suggest the car be sent back to newborn state. It may help...

[Dash74]

Hi. I'm new on this forum. I come from France. I have the same error message " défaut charging system " . The alternator have been changed 2 months ago. At the begining 0 problems and 3 weeks ago this error. Now, this message and leave quickly.
Whats the " reborn process " ? Reset of the D4 with iidtool ?

Thx a lot and sorry for my fr'english ;)

[veebs]

Hi. I'm new on this forum. I come from France. I have the same error message " défaut charging system " . The alternator have been changed 2 months ago. At the begining 0 problems and 3 weeks ago this error. Now, this message and leave quickly.
Whats the " reborn process " ? Reset of the D4 with iidtool ?

Thx a lot and sorry for my fr'english ;)

Hi Dash,

Your fr'english is much better than my en'french!

I'm not 100% on newborn state and how to get there, however I don't believe it is possible with the IID tool. I think it involved removing the ECU and re flashing using the LR equivalent of a fresh install of MS Windows. Best bet is to bring it to a trusted indie I would think, perhaps quoting my experience as a prompt to solving quickly. I know the newborn state was a last ditch effort by my indie, having exhausted all other possibilities by then.

My fault reappeared very quickly after the problem originally appeared to be solved (ie, on the drive home after the new alternator was installed). Given it took your vehicle 2 months to re-error, it may not be the same problem?