[Resolved] Start stop error/alternator charge issue ongoing

[RattyMcClelland]

I've been chasing my tail with this issue for over a year now. Literally spent a couple of thousand trying to sort it and it still won't fix the issue. The garage I use are at a loss too.

I have a start stop error on the dash.
Also, if I start the van and let it idle, it won't charge the battery and will drain until it dies. If I blip the throttle even the slightest, the alternator kicks in and charges and runs fine, start stop error persists.
This does it every time you start the van no matter how hot, cold, 5 secs start intervals or 2 weeks.

No visible dash error codes or lights. Plugging it in says BCM issue.

We have replaced
The battery, multiple times and coded it in.
3 different brand new alternators,
2 different but same part number recoded BCM units,
New battery negative module (used identical part number).
Checked all wires that we can and nothing is broken or frayed.
Software updated and remapped again, still nothing.

I'm at a loss of what to do with this heap.
Hate it. Hopefully getting rid of it when the electric transitsporter arrives next summer but I'd like to solve this issue.
Luckily this issue doesn't stop use of the van.


Any bright ideas on what to check next?

 

[Howzat]

Have you looked at the start stop settings using an OBD coder like OBD11?

Disable auto start/stop ? | OBDeleven

On the Q3, this option is disabled and I really need this disabling (using the app) How do I enable this feature in OBDEleven? I am now assuming some long coding is required as the app can't

forum.obdeleven.com

There are some settings like voltage and temperature that may be screwed in your ECU and this could help set the correct values and/or diable start/stop altogether.
Not a fix as such and it probably wont fix the wierd alternator not charging at idle issue but it may be worth a look.

 

[Dellmassive]

post some pics of the stuff.

a T6 on idle wont charge the battery due to the stop start setup.

but should start to charge when a load is added . . . ie AC, heated seats, headlights, heated screen etc.

get a battery monitor and start posting the screenshots and logs so we can see the plots.

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Battery Monitoring -- How I Done It --

Battery Monitoring -- How I Done It -- Part #1 Battery monitoring is a very important part of your 12v system . . . . whether its just the vans starter battery or your leisure setup keeping an eye on the power in your battery bank will keep you from breaking down and make sure your weekends...

www.t6forum.com

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...

https://amzn.to/3Rux82O

 

[RattyMcClelland]

Will get screen shots early next year when back at the garage if they have one.

I can load up the system at first start idle, like heated screen and my amps and the battery light comes on after a minute or so. I have to blup the throttle to initiate charge.
Idling/charging after the start up and initial blip or driving is absolutely fine. Just that first time restart of any journey it does it.

 

[jayc001]

I know you said you'd checked wires but have you metered out the yellow/green wire that can fail under the engine loom. Can't remember it's use but mine went recently and it gave stop start errors and charging issues. Think it's BCM to alternator loom. There details and pics on VCDS forums.

10 min job to splice if break found, bit longer to meter out but mine had no obvious visual break.

 

[RattyMcClelland]

I know you said you'd checked wires but have you metered out the yellow/green wire that can fail under the engine loom. Can't remember it's use but mine went recently and it gave stop start errors and charging issues. Think it's BCM to alternator loom. There details and pics on VCDS forums.

10 min job to splice if break found, bit longer to meter out but mine had no obvious visual break.

I'll add that to the list of things to check.

 

[Pauly]

Thats probably the LINBUS cable which is a single core for the van to communicate with the alternator (the so called smart bit)

 

[Stay Frosty]

I've got a stop start error that I got our local main stealer to look at and initially, probably due to previous experience, the mechanic there picked apart the loom running to the alternator and showed that one of the cables had turned from copper into green sludge.
Replacing the rotted section and rebundling this thin loom they told me I could come and get the van and that I would get charged just for the hours labour including the original diagnostic check.
Sadly by the time I got there the tech concerned said that the stop start error returned when they drove the van down the road and back and were rereading the original VCDS data but as I had had the cam belt and water pump by an independent wanted to replace those again even though they had covered 8,000 miles in the two years since replacement and as the independent garage pointed out if you don't have coherence between the cam and crank position sensors the thing won't start.
I'm not saying you can't trust main dealers but pointing out what the independent had said to the VW tech and he did say well quite often it's the cam position sensor or more likely the loom to it as it cooks where it runs over the top of the engine by the top mount charge cooler.
The stop start error is still present and will be an issue at some point in the future but for now drives normally but no stop start so one less button to keep pushing when we go out!
Should have said but this is on a 2017 102 engine at 55,000 miles

 

[RattyMcClelland]

Thought I'd update this.

After much fault finding we found the issue.
It was a break in the Linbus wire from battery negative module to the alternator.
The whole wire looked perfect, but after testing continuity every few mm across the wire we eventually found where it had smapped. Right bang in the middle near the sump.
No visual breaks but we bent it and it snapped and powered instantly.
Resoldered and now properly working for the first time in 2 years nearly. Start stop is back and smart charging.

Let's hope its reliable until the summer when it goes

 

[jayc001]

That's exactly where mine went. Luckily I found the info on Ross Tech website so located break straight away. Trouble shooting that without the info would be a nightmare.

 

[Dellmassive]

That's exactly where mine went. Luckily I found the info on Ross Tech website so located break straight away. Trouble shooting that without the info would be a nightmare.

God a link to that info?....

For others to refer too.

 

[mmi]

For others to refer too.

Perhaps these would also help:

VW TRANSPORTER 2017. ALTERNATOR NOT CHARGING. TRIED NEW ALTERNATOR, STILL NOT CHARGING.

Hi there any advice would be much appreciated! Wednesday,28,July,2021,11:31:54:20013 VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64 VCDS Version: 21.3.0.0 (x64) HEX-NET2 CB: 0.4543.4 Data version: 20210226 DS325.0 www.Ross-Tech.com VIN: WV1ZZZ7HZHH119698 License Plate...

forums.ross-tech.com

VW T6 stop start error message in dash

Hi looking for help on this van new to VCDS Getting message on dash stop start error once its started and ready to move. it also stays in vehicle status when you scroll through menu. I replaced the auxiliary belt as it was squeaking when weather damp in mornings. Battery also replaced as it was...

forums.ross-tech.com

Help! No more electricity from the alternator? Or something else?

Hi! I'm stuck with my clients, fault on the car. I have a Caravelle T6 from 2016 July. I was driving last night when the red light came (battery logo on the dashboard). I used my bluetooth OBD to check : 12,2v when engine running, to 11,7 then I stopped the engine. I checked the voltage...

www.t6forum.com

 

[Dellmassive]

Quote from above:


"Coming to look at it, have a look at T10i (dark brown 10pin connector in e-box). This way, you don't have to look at the BCM directly, but take the LIN port on the BDM (negative battery terminal). We know that line between the BCM and the BDM is working fine. Saves you a couple of metres of wire and the hassle of disconnecting the BCM.

I believe to have deduced that your problem is within the orange square:"

++

"FIXED. I HAVE NOW HAD 3-4 OF THE SAME VEHICLES WITH THE SAME FAULT NOW. SEEMS TO BE A VERY COMMON FAULT.

THE BRAKE IN THE LIN WIRE FROM ALTERNATOR IS ALWAYS IN THE SAME PLACE. FOLLOW THE WIRE FROM ALTERNAOTR INTO THE LOOM AND JUST BEFORE WERE THE LOOM STARTS TO GO UP THE ENGINE BAY IS WHERE IT BRAKES. OPEN PLASTIC CASING AROUND LOOM AND PULL ON YELLOW AND GREEN WIRE, IT WILL SNAP EASY.

SEEMS TO BE WHERE WATER SITS INISDE/THE LOWEST POINT OF THE LOOM AND CORODES THE WIRING."
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VCDS SCAN
-------------------------------------------------------------------------------
Address 61: Battery Regul. (J840) Labels:. 1K0-907-534.clb
Part No SW: 7E0 907 534 HW: 7E0 937 090
Component: Batt.regelung H81 0744
Serial number: 0982 018171093
Coding: 330B7A73
Shop #: WSC 61351 001 1048576
VCID: 6882D27D5277399B273-803C

Subsystem 1 - Part No SW: 7E0 915 181 K HW: 7E0 915 181 K
Component: J367-BDMConti H03 1050
Serial number: 75410903921701201094

1 Faults Found:
02252 - Generator
004 - No Signal/Communication
Freeze Frame:
Fault Status: 01100100
Fault Priority: 2
Fault Frequency: 1
Reset counter: 190
Mileage: 118429 km
Time Indication: 0
Date: 2021.06.28
Time: 09:59:19



++++++++++

 

[Jamesbolt]

View attachment 227028

Sorry to ask but where does the red/grey wire go?

I'm having troubles with starter battery charging and I have found brake in yellow wire but still getting an fault coming up.

It's 00088 Charge monitoring for starter battery.
012 Electrical fault in circuit - intermittent.

So I thought, perhaps, the other wire at fault? Any ideas? Thx

 

[Dellmassive]

Sorry to ask but where does the red/grey wire go?

I'm having troubles with starter battery charging and I have found brake in yellow wire but still getting an fault coming up.

It's 00088 Charge monitoring for starter battery.
012 Electrical fault in circuit - intermittent.

So I thought, perhaps, the other wire at fault? Any ideas? Thx

got a pic?

yellow is normally a repair wire . . . ie a plug pin crimped to a length of yellow wire.

.

 

[Jamesbolt]

Sorry, I was referring to the diagram above. The yellow/green wire is going from battery control unit(j367) to alternator (that is where I found the break and repaired it). I wonder where does the red/gray wire go from j367.

 

[tomosllyr]

For anyone who's done this repair - how easy is it to access with a jack and axle stands? I'm pretty sure I have the same issue based on symptoms.

 

[jayc001]

Easy. No more than a 30 mins job. Finding the faulty cable was surprisingly easy. I remember when doing mine it was fricking freezing much like current weather.

 

[tomosllyr]

Easy. No more than a 30 mins job. Finding the faulty cable was surprisingly easy. I remember when doing mine it was fricking freezing much like current weather.

Thanks for this. Roughly where under the van am I looking for the problem in the loom?