And if it is stop start replace both batteries local main dealer had a car x6 times and couldn't find a fault so this person I know got so fed up he bought a new car and left his D4 on the driveway we replaced his second stop start battery and its fixed it.

Smug or what

Awgodsall said:

What other ideas do u have. I’ve asked them to check the alternator make. I do appreciate your help gstuart as I do all the other people that have commented and offered advice.

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no probs and as u asked so nicely happy to help where I can

firstly plus 1 what @Mark Piercy has mentioned ref the 2 x batteries and the BMS module

would really help if u got some form of diagnostic reader and a multimeter , will,pay for themselves very quickly along with being so handy to keep in the vehicle

if the batteries all check out and u still gettting the eco error to me that points towards the gearbox, when u get the error I assume the stop start no longer works until u Cycle it, ie resetting it like u would with a computer

that can be bad pins at the mechatronic connection , or loom going to it, bad earth , but of course the alternator and batteries , earths have to be 100% ok , before doing anything else

u can test the canbus yourself using a basic multimeter , if u would like me to talk u through that am happy to do so , must confess when I first bought my D3 some 6 x years ago I knew nothing about canbus , having a nice dad , lol, he treated me to a lot of the test equipment , seeing the canbus is the electrical backbone of the vehicle of how all the modules talk with one another so learnt a lot and saving a fortune along the way , ie a breakout box with the leads that allows u to test systems in more detail , but that’s further down the road so to speak if u wish to get a lot more involved

wonder if it’s worth getting some battery monitors , ref BM2 , there only around £20 for each battery and very easy to fit There used via an app on ur iPhone or iPad , u will be able to do several tests , , enclosed some screen shots for u

plus more screen shots of that Autel AP200 , another great basic tool as having fault codes is half the battle , then with them it helps considerably trying to pin faults down

my concern is u having to pay garage fees that can accumulate very quickly, moreover no accurate cure to the faults

personally would get some BM2 battery monitors , multimeter and Autel AP200 , consider them as an investment as these motors really do need some basic tools or ur keep having to pay out everytime a fault shows up, plus of course having them yourself it’s the convenience in not having to wait for an appointment

know There not a substitute for vast experinace or very expensive scanners but is a very good start asit At least gives u some idea of where to look

hope that helps and indeed as I mentioned as u asked so nicely happy to help where I can, always a team effort seeing there’s around half a dozen of us that know these motors very well as we have our own little speciality so to speak

BM2 battery monitor , need one for each battery

Amazon product

Autel scanner

Amazon product

also with this being intermittent at least with the battery monitors ur be able to see both batteries , the aux battery do get overlooked a lot

know it can be frustrating but working through these step by step is key , not rushing but a slow methodical approach

hope that also helps u

Multimeter wise, uni t are very good


Amazon product

gstuart said:

BM2 battery monitor , need one for each battery

Amazon product

Autel scanner

Amazon product

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Hi Gary, wonderful advice for the op as ever from your good self.
Sorry to cut in on this thread but with ref to the battery monitor, can you/do you leave them connected permanently?
Many thanks, Andy.

Many thanks for the advice. Really appreciate it.

Andy Warren said:

Hi Gary, wonderful advice for the op as ever from your good self.
Sorry to cut in on this thread but with ref to the battery monitor, can you/do you leave them connected permanently?
Many thanks, Andy.

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hi Andy

thk u so much , indeed u do in leaving it connected all the time , range sadly is only around 20 x feet via Bluetooth but me being lazy sitting on the sofa I’ll a readout, lol

it comes with a free app but I got a multi battery app which allows u to monitor up to 4 x batteries , just need a BM2 on each battery , just found it a great tool for not much money

found a video as well for u mate and allows u to do other tests , plse see What u think

Awgodsall said:

Many thanks for the advice. Really appreciate it.

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ur so welcome mate , forgot to add if u do get a BM2 for each battery ur need a multi battery app for a few quid , will find the app

plse let us know how u get on and if u get stuck plse give any of us a shout

Found the app for u both of u if u use more than one BM2 battery monitor , this is what ur able to do which I think in this circumstances will be perfect where u can monitor the battery voltages etc

can’t find the price at the moment for the app, but think I paid £5.00 which is then free for life and can use it on multiple devices

Really hope this is useful

I’m have ordered the battery monitors and the code reader I already have a multi meter. Does the app record what’s happening as the fault happens when driving it would be really useful to see what’s happening with the battery when it happens.

Awgodsall said:

I’m have ordered the battery monitors and the code reader I already have a multi meter. Does the app record what’s happening as the fault happens when driving it would be really useful to see what’s happening with the battery when it happens.

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that’s brilliant mate in ordering the 2 x BM2 and the code reader

indeed it will keep giving u a voltage read out whilst driving for each battery so u can look back through the history to see what the voltages are , done it myself and so handy

what multimeter have u got plse and at least that saves u some money already having one

then having the items urself above u won’t have to rely on a garage or wait round for appointments, once u get the scanner it’s best to do a full scan, note everything, / print it out, clear everything then re scan to see what comes back

the look for the BMS reset for each battery , first ensuring there both fully charged , the app will tell u what the voltages are

plse make sure y change the app from lead acid to AGM on each one

glad it’s helpful to u

I did also add an aux fuse box and a combined main / air voltage gauge , this was before I was aware of the BM2 apps ,

also added a 3.5mm aux socket , inside cabin temperature and some USB/ C charging points in the centre dash

Meant to add here’s a screen shot of where the battery monitor will Show Vdc data whilst driving for each battery , so hopefully ur be able capture any glitches

would monitor this first before resetting The BMS module, just so u can catch it, then after resetting the BMS if it stops u know that was the issue

it should also give Vdc data whilst the disco is parked up

hope that makes sense,

gstuart said:

hi Andy

thk u so much , indeed u do in leaving it connected all the time , range sadly is only around 20 x feet via Bluetooth but me being lazy sitting on the sofa I’ll a readout, lol

it comes with a free app but I got a multi battery app which allows u to monitor up to 4 x batteries , just need a BM2 on each battery , just found it a great tool for not much money

found a video as well for u mate and allows u to do other tests , plse see What u think

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Hi Gary, thanks a million you diamond geezer you. I'll get one on order, although I've not had any issues (I think because I leave my solar panel charging through the OBD when the D2 is not in use) I like to know what's going on , all the best.

Andy Warren said:

Hi Gary, thanks a million you diamond geezer you. I'll get one on order, although I've not had any issues (I think because I leave my solar panel charging through the OBD when the D2 is not in us) I like to know what's going on , all the best.

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lol, ur so welcome mate and pleased it’s of use

indeed so very useful having one , along with the break out box and multimeter, therefore reducing the risk of the OBD2 pins getting damaged

at the end of the day amazing how much knowledge u pick up over time , was the same after rebuilding my air suspension system

plse let us know how things go

Update I w had the car back a few days seems to be behaving. I managed to get the dealership I bought the car from to pay for the battery. I w scan fed the car and am suppressed by the amount of codes that are on there. I cleared everything again even though the garage had done the same. Took the car for a drive and is will add a picture of what was picked up on the scan when I returned home. The car however hasn’t lit up like a Christmas tree yet.

Oddly the date on that is may 22

Awgodsall said:

Hi all do the disco has been in the garage since Tuesday. Brilliant group of guys. They know it’s loosing its high speed can-bus. But they’re having a hard time finding what the cause is. Typically the car has behaved itself on the four test drives they have done. But they’re leaning towards either the battery because the one on there is not a good quality make or the battery monitoring system. There is a relatively new alternator on it which tell me that this problem has been on the car for a while. Why did I have to buy one with electrical gremlins lol

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What make is the alternator? cheap ones or recons on d3/4 don't do well and cause all sorts of grief.

It’s a relitively new denso