Having electrical issues battery or stop/start

[YorkshirePud]

Hi everyone I'm having some sort of electrical gremlins with my Leon. It's booked in for work soon so im hoping this might solve the issue but until then i've been trying my best to either diagnose the issue myself or fix it with my limited skills and resources. Apologies this is a long thread!

so the main things first and foremost
Leon 3rd 1.2TSi 110 2014 un modified.
car regularly service. approaching 60k mostly does motorway miles through week 30 mile round trip to work.

video link of issue:

The problem appeared out of nowhere last wednesday morning i jumped in the car to go to work turned the ignition to on and blip! everything just went dead. Nothing. couldn't even lock the car. Opened the bonnet to see if anything obvious was amiss and no. So for all the good it did i tried again and got nothing except for the dash and middle display flickering a bit before dying. Called the AA out. patrol tested battery and said it was fine. He wiggled the terminals a bit and told me to start the car and it damn well started! So went to work. But since then the issue has appeared over 5 times and is a real headache. I seem to be able to get the car going. AA have been out to it again and tested battery again, tested alternator and still nothing obviously wrong. Patrol could not see any issues on grounding points he could see either.

report is as follows:
Patrol found the following fault code/s:System : Engine control - VMC / Motronic MED 17.5.25 UDS Status :U112300 - Data bus. Error Message : Signal reception. Static fault. Status :U042800 - Steering wheel angle sensor. Error Message : Signal improbable. Static fault. Status 044100 - Fuel evaporation system. Error Message : Flow rate faulty. Sporadic fault.No fault apparent, battery tested and passed, charging system ok. All ok. Engine Oil Level Ok. Coolant Level Ok.

for some reason wiggling or disconnecting the terminals and then giving it a minute or two seemed to work. I eventually had the idea to disconnect the cable/plug onto the negative that i read once was to do with the stop start system. As soon as i did that and tried to start the car it started straight away! and it worked absolutely fine all day yesterday, it got a good run out and i thought that might keep it sorted until i can get it to my preferred mechanic.

through desperation i also bought a carista just in case. the details from that fault are below:
CAN network gateway
Part #: 5Q0907530T
Component: GW MQB High
Software version: 1188
ASAM/ODX identifier: EV_GatewLear
Coding: 030100F42B085700EF000048080F00010001000000000000000000000000 (hex)
[No fault codes]

Central electronics
Part #: 5Q0937084AJ
Component: BCM MQBAB H
Software version: 0134
ASAM/ODX identifier: EV_BCMCONTI
Coding: 0B000A424201005B0B244000B10403081000000000000000000000000000 (hex)
Fault codes:
197644 Control circuit for fuel tank flap (electrical failure)

Steering wheel
Part #: 5Q0953507AC
Component: Lenks. Modul
Software version: 0070
ASAM/ODX identifier: EV_SMLSKLOMQB
Coding: 1400 (hex)
[No fault codes]

Airbags
Part #: 3Q0959655AC
Component: Airbag VW20
Software version: 0189
ASAM/ODX identifier: EV_AirbaVW20TS6VW48X
Coding: 98CCC000000000005C0000CC008800000065 (hex)
[No fault codes]

Instrument cluster
Part #: 5F0920972
Component: KOMBI
Software version: 4270
ASAM/ODX identifier: EV_DashBoardVDDMQBAB
Coding: 27A50A002980260001087A001000000000000000 (hex)
[No fault codes]

ABS
Part #: 5Q0907379K
Component: ESC
Software version: 0371
ASAM/ODX identifier: EV_Brake1UDSContiMK100ESP
Coding: 18EE8A9224202974007E060941C9241851249400608224F200210070C002 (hex)
Fault codes:
00297 Transmission Vehicle Speed Sensor (G38)
16390 Fuel Shutoff Valve A, Circuit Low

Power steering
Part #: 5Q0909144P
Component: EPS_MQB_ZFLS
Software version: 1043
ASAM/ODX identifier: EV_SteerAssisMQB
Coding: 0103 (hex)
[No fault codes]

Heater & air conditioning
Part #: 5F0907426H
Component: AC Manuell
Software version: 0705
ASAM/ODX identifier: EV_ACManueBHBVW37X
Coding: 04100004200100001000000000001000 (hex)
[No fault codes]

Front passenger's door
Part #: 5Q4959592B
Component: TSG BFS
Software version: 0014
ASAM/ODX identifier: EV_DCUPasseSideEWMAXCONT
Coding: 00100220C401040100001000 (hex)
[No fault codes]

Driver's door
Part #: 5Q4959593B
Component: TSG FS
Software version: 0014
ASAM/ODX identifier: EV_DCUDriveSideEWMAXCONT
Coding: 00100220C001040100001000 (hex)
Fault codes:
65548 Manufacturer-specific code

Headlight aiming
Part #: 5Q0907357
Component: LWR-ECU
Software version: 0080
ASAM/ODX identifier: EV_HeadlRegulVWLWRMQB
Coding: 048C000009000000 (hex)
[No fault codes]

Engine
Part #: 04E906027CJ
Component: 1.2l R4 TSI
Software version: 7798
ASAM/ODX identifier: EV_ECM12TFS01104E906027CJ
Coding: 01190012232419080000 (hex)
Fault codes:
17158 Manufacturer-specific code
07150 Manufacturer-specific code

Infotainment system
Part #: 5F0035858A
Component: MU-S-ND-ER
Software version: 0480
ASAM/ODX identifier: EV_MUStd6C1PASE
Coding: 04731001D70A000021111101000800002F0106060100010046 (hex)
Fault codes:
01555 Motors for central locking, SAVE

despite thinking my temporary fix might have worked it did not. and the car once again refused to start. I cannot get the car looked until the following tuesday. I live alone and have nobody else to currently fall back on for transport to and from work so i needed to get the car into some sort of working order. So i bit the bullet and went to get a replacement battery from halfords just to see if this might fix it. I also got it tested again while i was there. Both halfords and AA tests say the battery is FINE!

So i fitted the battery and registered it. Had some difficulty there as i didnt know the manufacturer code (i know their own brang agm battteries are made by yuasa but whats the code) Also couldnt read the damn serial number. But i did input the right amperhour and battery type.

cleared all errors. took the car for a ride with stop start disabled and its been fine. I did turn on stop start (using button in car) when i reached home to see if it would cut in but it did not and just threw the centre display stop/start error at me.

I've now reached the end of my skills and resources. If this new battery doesn't fix it i am a bit screwed until i can get it to a garage. If anyone knows of similar issues or can make sense of what i have put down so far that would be great. I've done as much searching as i can but couldnt find anything matching it.

 

[black_sheep]

I’m afraid that I haven’t got time to look at this in any detail this evening, but will try to look later. However, for the manufacturer’s specific codes use the Ross-Tech wikis here:

Ross-Tech Wiki

wiki.ross-tech.com

The quickest way to find what you have is to use Google search ‘ross-tech wiki + fault code’

These pages describe the individual faults and a check list of possible causes.

However, most of what has come up indicates a battery fault - the fact that you wiggle the terminals and everything works, would be indicating a break in the loom/bad earth/loose plug/bent pin in a plug somewhere.

 

[chrisRibiza]

Low battery charge throws up all sorts of errors like this.

id 100% start with a new battery and go from there.

 

[RUM4MO]

Out of interest, did you buy an EFB battery and one that was at least the same CCA either EN or DIN rating as the original and the same or higher amp-hour capacity?

All the BMS needs other than the capacity is a serial number change, just add "1" to the original would do.

 

[YorkshirePud]

Thank you very much for the replies so far! The new battery is in and I re-registered the new battery with the manufacturer code YB <with a space after the B) and then as suggested upped the serial with one number.

The new battery is an AGM I would have gone for a EFB but sadly Halfords don't stock one in that size and as late on Sunday as it happened I didn't have a choice. Fortunately all the vital stats for the battery match or exceed. I double checked before installing.

I will look into the wiki for the fault codes too that's excellent thanks. I don't know if it helps but I also did a short video tracing as much of the cabling as I could in the failing light. Off on a video chat with friends now to try to forget all this haha. Thanks again guys.

 

[RUM4MO]

Looks good enough, on the "swopping EFB for AGM" , when you were changing things, did you change the "technology" from "EFB" to "fleece" probably not a show stopper but more a "better to do" for the long time future of the new battery.

 

[YorkshirePud]

Looks good enough, on the "swopping EFB for AGM" , when you were changing things, did you change the "technology" from "EFB" to "fleece" probably not a show stopper but more a "better to do" for the long time future of the new battery.

Not quite sure what you mean by "fleece?" i did change the battery type to AGM should it be fleece instead?

Without trying to jinx things, the car has behaved over the last few days. Since i also went back in and edited the manufacturer code and serial number I've had no stop start errors thrown at me. Though i have disabled it manually the every time I've jumped in. Just want to make sure the battery is behaving and being charged correctly first. will give the stop start a go in a few more days. I know i can permanently disable it using carista and i am, considering it. My current commute is the full length of the M57 so the car gets a damn good run each day and i rarely end up in a stop start situation. even when im not commuting so may just kill it all together. BUT lets see how it settles down with the new battery first.

Appreciate the replies again folks!

 

[RUM4MO]

There seems to be a general agreement on these VW Group forums that "fleece" is the battery tech option for these standard construction AMG batteries, the mat "M" part of AGM seems to translate into "fleece" in Germanic speak, AGM and the other AGM option are for other types of battery construction, even CTEK take that line, ie for charger options EFB is the same as normal AGM, other AGM construction needs the AGM setting.

Edit:- my interest in getting these facts right stem from preparing myself for when my wife's 2015 Polo asks for a new battery!

 

[YorkshirePud]

Given the fun i have been experiencing rum4mo i do not blame you! I will have a look at the weekend to see if there was a fleece option in the carista app. But i don't recall seeing it in the drop down box when configuring the battery. I would have picked AGM since i know that is what the battery type is. or is at least labelled as. I know its made by yuasa even if it has halfords slapped on it.

 

[RUM4MO]

I'm afraid that I went a bit further in my preparations for that "battery no good" day, I bought the next size up battery tray and battery heat shield, as the petrol engined Polos, excepting the GTIs, below the TDI engined cars were fitted with a smaller battery tray which is filled completely by the correct size of battery.

I'll be almost disappointed if my wife's 2015 Polo never needs a new battery!

 

[YorkshirePud]

That's some decent forward thinking. Not splashing out too much on the Leon as i am not sure now how long i will hold onto it for. Bit disgruntled ive had to change the battery so soon. The diesel ford focus i owned from new before this the battery lasted 10 years! absolute tank.

Just an update as well for those following let's just say the car is currently behaving as well and leave it at that for now

 

[BoomerBoom]

Seven years isn't a bad life for a modern battery; they are made of the minimum of materials, never have the electrolyte topped up but very often have to provide huge current flows to stop-start - also the constant draw of all the electrical kit onboard these days.

 

[YorkshirePud]

Of course, when i worked it halfords you quickly realised judging by the age of cars that were coming in for first batteries what the average was. Just couldn't believe how long the battery in my old focus kept going. I used to joke it must have come out of the ark of the covenant haha. even odder was that battery was subjected to at least 5 years of really short journeys.

Might let the stop and start kick in today and see if it throws up any errors. tempted to turn it off anyway with carista as mentioned but may hold off until its been serviced and those other errors have been investigated furthur.

 

[martin j.]

Is it possible that the fault was internal to the battery? Wiggling leads remade a poor connection inside it and when connecting a tester was enough to maintain a good supply. Just wondering like.

 

[Slickric21]

Interesting thread this, i think ive had similar issues with my 2019 R ST. It regulary sits on my drive for days on end and has only done 7k miles in 2 years - many of them shirt trips.

I keep regulalry getting fault codes relating to electrical stuff similar to the OP, I clear with OBD11, but they return intermittently.

I'm thinking of replacing the battery for a matter of course, and cant be bothered with having it looked at under warranty.

Looking at replacing the oem EFB 69a battery with AGM one, which should be better for this car anyway (with stop/start and all the electrics onboard).

Think i'll get the Exide EK700 AGM one, looks good price at £87 off Amazon.

Anyone know the Manufacturer code for Exide batterys to use in OBD11 btw (i know about changing to fleece and changing serial number) @RUM4MO perhaps you know this ?????

 

[YorkshirePud]

Anyone know the Manufacturer code for Exide batterys to use in OBD11 btw (i know about changing to fleece and changing serial number) @RUM4MO perhaps you know this ?????

This has just reminded me to check the option for that in carista again before i set off out in car. But i should note its been fine while its been set to AGM.

Happy to report the car's had an oil service and a looking at by my trusted garage. My guy has given everything the once over and aside from an oil change and pumping up the tyres she is in very good nick apparently! He's also cleared out all the codes for now using is diagnostic tool which is no doubt more sophisticated than carista.

He also said he wasnt surprised changing the battery fixed the issue. He said testing the stop start batteries is a bit pointless these days as it might have one bad cell that buggers everything up.

Fingers crossed guys!

 

[RUM4MO]

@Slickric21, I'm guessing that your current battery is not an Exide?

My wife's 2015 Polo has an Exide so I can check what the manufacturer's code for that is, although I think that VW just leave everything as default at factory which means battery manufacturer is left as JCB and battery serial number is left as 111111111!

Edit:- I'm guessing that your car was fitted with a Moll battery at factory and so has a manufacturer code of MLA - checking my info I have collected from all our family cars, both my wife's 2015 VW Polo and my mate's 2018 VW T-ROC, the battery manufacturer is listed as JCB and they both have factory fitted Exide batteries, and both have serial number 111111111 - so none of that is what you asked for, sorry.
If in doubt use JCB as it seems to work okay but as I said is more than likely just a default as JCB do or did make batteries for some battery brands. That JCB is just Johnson Controls Batteries and not anything to do with real JCBs!

 

[Slickric21]

@YorkshirePud i’d probably change it to Fleece if you can do it easily enough, that’s the correct option and whilst it may not be so important, if you can why not ??

@RUM4MO that would be great thanks. The original battery is the OEM one (69a EFB), I think it just says on it ‘Volkswagen Group’ I’ve not had it out fully yet so not had chance to inspect the labels and it’s covered up by my ABT module, but in OBD11 it’s listed as ‘MLA’ as manufacturer.

I’m hoping It’s not that important, but if I can change it easily enough with OBD11 I’d like to

 

[YorkshirePud]

Seems logical to change it if two people have suggested it! I will make sure i check when i next hop in the car, and if i can i shall! I've also posted in the carista thread since i've started tinkering with that. but thats another

When i registered the new battery details using carista i just set the amprehours and battery type. I changed the manufacturer to YB_ (where underscore is just a space) this covered the 3 character limit in carista. For some reason it doesn't accept the battery serial number. and it is barely readable on my new battery. But as @Rumadm8 helpfully suggested i just upped the previous serial number by one figure. and presto it worked ok. the most important thing seems to be battery type and Amprehour.

 

[RUM4MO]

@YorkshirePud i’d probably change it to Fleece if you can do it easily enough, that’s the correct option and whilst it may not be so important, if you can why not ??

@RUM4MO that would be great thanks. The original battery is the OEM one (69a EFB), I think it just says on it ‘Volkswagen Group’ I’ve not had it out fully yet so not had chance to inspect the labels and it’s covered up by my ABT module, but in OBD11 it’s listed as ‘MLA’ as manufacturer.

I’m hoping It’s not that important, but if I can change it easily enough with OBD11 I’d like to

I've just watched a youtube video covering changing battery codes in the BMS module, and it lists some, but not all battery manufacturer's codes:-
JCVJCB is JCB, Exide is TU3, Varta is VAO(or is that 0?), Bauer is BA2, Acuma is UM5 and Moll is MLA.

Now, I know that Moll = MLA is true, so maybe Exide = TU3 is also true - if it is not, then the BMS module will not accept that input so worth trying that I'd think for your Exide battery.