Stop/start error after battery swop

[Plumberman]

Hi. Just fitted a new 95ah starter battery after which the MFD is showing a Stop/Start error when switched on. Also Carista is showing Battery Monitor Module fault. Battery has been registered with the Carista. Any thoughts and is the van ok to drive? Thanks for your thoughts.

 

[Dellmassive]

Post a few pics of the starter battery and connections.....

 

[Plumberman]

Thanks Dellmassive. I'm pretty sure all connections are as before. Any thoughts?

 

[roadtripper]

"Battery Monitor Module Fault" makes me thing the issue is either to do with the shunt or the LIN bus wire to it - especially if it only happened while you were changing the battery.

The LIN bus wire does seem fragile so it's possible that disturbing it has caused an issue.

How old is your van - the engine bay looks pretty clean and tidy...

 

[roadtripper]

Just coming back to this.

So after replacing this module I had the same errors, my problem ended up being the green/yellow wire being broken (somewhere) between BCM, this battery module and the alternator.

I ended up rewiring all, and fitted a new LIN wire from BCM, to alternator, to battery module. My alternator, stop start, and battery monitoring control module errors then went away.

 

[Plumberman]

"Battery Monitor Module Fault" makes me thing the issue is either to do with the shunt or the LIN bus wire to it - especially if it only happened while you were changing the battery.

The LIN bus wire does seem fragile so it's possible that disturbing it has caused an issue.

How old is your van - the engine bay looks pretty clean and tidy...

Van is only 3 year old and 4000 miles. I think the old battery had suffered from la k of use. Other than the Stop Start issue everything else seems ok.

 

[Plumberman]

Just a thought, we're away from tomorrow in the van for a couple of weeks, am worried that the stop start problem will cause other issues. Any thoughts? Thanks

 

[roadtripper]

If it's just a lack of communication between the BCM and the shunt then that should be low risk - the van should fall back to not using start stop and doing less intelligent charging as it will not be able to work out the battery state of charge.

Hopefully you have breakdown cover - and take Carista with you so you can check if anything further crops up?

I would just try and double check the connection to the shunt though and check the wire run right next to the battery.

 

[Dellmassive]

Thanks Dellmassive. I'm pretty sure all connections are as before. Any thoughts?View attachment 245934

so its a T6.1 with stop start etc. . .

after a battery disconnection you will need about 2 or 3 drive cycles to clear all the dash errors,

then about 10 drive cycles for the system to calibrate the full charge point etc...



also the battery needs coding to tell the system the Capacity and SoH.

+++

Upgrading Starter Battery - how to guide

My van (April 2017 T28) is fitted with a Moll battery. I am experiencing some issues with it not starting after a few days sitting on the drive. Now this could be due to the tracker I have fitted draining it but I doubt it, I'll do some drain current tests before taking the plunge. If I were to...

www.t6forum.com

+++


if its LIN bus comms issue with the battery monitor, then @roadtripper has mentioned that above.

its the white box with two wires on thats connected to the NEG battery clamp. - make sure its seated correctly.

.

 

[T6_FunBus]

Run it for a while, it won’t work until several start stop cycles. It’s normally unhappy for a bit when battery removed / changed or replaced. It will not say ‘stop start error’ unless there is an error in the system. It will say ‘stop start not possible’ if there is not an error but the conditions are not met. If there is an error, and the battery module is throwing an error, check the two wires on the shunt.

If the alternator end is broken you will get ‘lost communication with bcm’ and ‘generator’ fault codes. If it is the shunt or a wire on the shunt to the bcm, you will get errors in the battery control module.

The two small wires can break. I completely rewired my alternator and bcm, but then shortly after got start stop and battery module errors. On closer inspection, the wire sheeting had split where it bends when attached to the plug. In the end I cut the wires, removed the pins from the plug, soldered two new wires on, refitted the plug, and soldered the new wires to the old loom. The small plastic nib is meant to press into the tray beside the battery and take the loom weight so it doesn’t fracture the wire. But also, as the wires are bent to the side and vibrate a lot, I guess the can also get damaged.

Unfortunately no sure fire way of telling unless you can actually see a break or damage, or test wire continuity either end of the loom (which is a ball ache) or, replace connections and wires and hope.

Fingers crossed you sort it. Electrical issues on these (and VWs in general as I have learned) are a total pain in the ass.

 

[Plumberman]

Thanks for all your replies. I pretty sure it's LIN wires, they took a bit of a be bash when I slotted in the new battery. Am away for a couple of weeks in the van at the moment but will look to check continuity when I get back. Other than start/stop everything else seems ok, battery charging and no other problems. Thanks