Is my alternator dead?

[eetmw]

So, relatively new, good quality battery. Been doing a few shorter journeys. Battery light came on while driving a few times and when i went to put Carista on after a day or two it would not start as it said the battery was too low. I charged the battery up plugged in and there was a fault code.
02252 Generator, no signal communication.
The engine is also revving slightly higher than usual at idle (1000 vs 900 ish) and fuel economy is a little better??

I fully charged the battery last night and then drove to swimming 25min A road and duel and coming back the battery light was on again.

Caravelle t6 euro 6 150 manual

Could this just be a corroded wire under the engine or has the part failed?

Many thanks

Toby

 

[DaveD]

I think you are right to suspect alternator failure, but I'd remove the electrical plug on the rear of it and clean up the contacts with something like electrical contact cleaner then try it again before buying a new alternator, you've not got a lot to lose by trying that first.

 

[oldiebut goodie]

It does sound like its the often reported LIN-Bus wire failure. There are a lot of posts on this. A search should reveal them. Unlikely to be the alternator itself. ( the diagnosis tells you it is the wire/signal )

 

[eetmw]

Thanks for the advice, took the van for a short drive today that turned into a longer one when a regen started and from fully charged the battery light came on minutes into the drive and the battery has run down a lot by the time I got home. Ho hum think I’ll get it booked into the garage and ask them to check the fuses, wiring and alternator.

Cheers

Toby

 

[DaveD]

Thanks for the advice, took the van for a short drive today that turned into a longer one when a regen started and from fully charged the battery light came on minutes into the drive and the battery has run down a lot by the time I got home. Ho hum think I’ll get it booked into the garage and ask them to check the fuses, wiring and alternator.

Cheers

Toby

Before you do that you might just want to check that the auxiliary belt that drives the alternator is tensioned correctly and appears in reasonable condition, if it's slipping that could cause your issues. Unlikely but it'll only take a minute or two to check it.

 

[eetmw]

Just an update, checked fuses, checked belt, all good, unplugged wire from battery ground and sprayed with contact cleaner. Just drove and no battery light came on. Still worried about the wires so will ask garage to double check everything next time it’s in.
Thanks for the top tips and support.
Toby

 

[Stay Frosty]

As @oldiebut goodie said it sounds like the thin green and yellow linbus communication cable has rotted out inside the corrugated pvc tube that covers a section of the harness where it goes along the underside of the front bumper on its way to the alternator.
The local main dealer here found it very quickly and the copper in the cable itself had turned to a slimy copper sulphate mush, the factory insulation must be made from custard powder but it's been good since the repair and hasn't returned.
Ironically though the rotted cable was found as the stop/start had stopped working and this was part of the 50,000 potential reasons for that failure although ultimately replacing the cam position sensor got things stopping and starting again so now I can override that again with the button on the dash!

 

[Fexin]

What’s the fix for this then? New lin-bus cable? If so does anyone have a part number?

 

[Stay Frosty]

You could open the corrugated plastic tube covering the harness going to the alternator and, expose the wires and give them a pull through their length to see if the copper is intact, particularly the thin green yellow wire or book it into a garage for them to do the same as part of their fault finding?
I hasten to add I booked mine into a VW garage as I hadn't asked on the forum first.