MG5 - OBD to reset HV battery issue

[mikedarby]

Hi. I've seen a number of threads where people have experienced an HV battery shutdown following a rapid CCS charge.
We experienced this on a road trip in Spain, and had a something of a nightmare getting going again. We ended up having to stay the night in a restaurant's store room - long story...
I had tried disconnecting the 12v battery many times, waiting anywhere up to 30 mins before trying again. As others have said the only thing that worked was when a (BMW) service engineer arrived and reset everything via OBD. This wasn't straightforward either and in the end neither of us was actually clear why the reset worked.

The car has been fine since, but obviously without knowing exactly what triggered the lock out it's nerve wracking using fast chargers far from home.

My question is does anyone know a particular OBD device and app combo that they have used to successfully reset an HV battery shutdown themselves with a degree of confidence?

Many thanks.

 

[Jomarkh]

What percentage did you charge to on the rapid charger?
Good to stop at 80% over 90 % may give you issues

 

[mikedarby]

What percentage did you charge to on the rapid charger?
Good to stop at 80% over 90 % may give you issues

Well, in this case the HV battery disconnect fault occurred before charging started, I.e. immediately as I plugged in. However, the charge before was on a fast charger and I did charge to >90%. In this case I was actually sitting in the car on a call for work (and keeping an eye out in case anyone needed the charger), so I charged longer than normal. I recall being surprised that the charging had stopped on its own at less than 100%, so it's possible the issue was triggered then, but didn't become apparent until the next charge.

Either way, still keen to find an OBD option that is likely to reset any future issues.

 

[5teep]

I have a cheapo obdii tool but it does not give any option to clear vehicle faults, only emissions. It's possible more expensive better featured ones will work but is it worth the money for the once or twice you encounter the cut off issue?

 

[emmrecs]

I have this from Amazon along with the Android CarScanner app.

I've never needed yet to be able to reset any error codes so cannot vouch for its effectiveness but the app certainly does offer that option.

I don't think it would make any difference to this facility but I have the Pro (paid for) version of CarScanner. For Android it cost just over £4 IIRC; for iOS it is rather more expensive, though still not very much. Why the iPhone/iPad version is more expensive I have no idea!

 

[slmorgan42]

I have this from Amazon along with the Android CarScanner app.

I've never needed yet to be able to reset any error codes so cannot vouch for its effectiveness but the app certainly does offer that option.

I don't think it would make any difference to this facility but I have the Pro (paid for) version of CarScanner. For Android it cost just over £4 IIRC; for iOS it is rather more expensive, though still not very much. Why the iPhone/iPad version is more expensive I have no idea!

I have the same device and software. Like you, touch wood, I have not needed it yet. I have used it to check SOH and link it to ABRP.

I am guessing the iOS version is more as apple take their %. PS i have an iphone and not having a go at apple or wanting to start a debate lol

 

[dragon2611]

Hi. I've seen a number of threads where people have experienced an HV battery shutdown following a rapid CCS charge.
We experienced this on a road trip in Spain, and had a something of a nightmare getting going again. We ended up having to stay the night in a restaurant's store room - long story...
I had tried disconnecting the 12v battery many times, waiting anywhere up to 30 mins before trying again. As others have said the only thing that worked was when a (BMW) service engineer arrived and reset everything via OBD. This wasn't straightforward either and in the end neither of us was actually clear why the reset worked.

The car has been fine since, but obviously without knowing exactly what triggered the lock out it's nerve wracking using fast chargers far from home.

My question is does anyone know a particular OBD device and app combo that they have used to successfully reset an HV battery shutdown themselves with a degree of confidence?

Many thanks.

I was going to try that but carscanner was being so slow to scan the various fault codes It was quicker to disconnect the 12v

 

[mikedarby]

I have a cheapo obdii tool but it does not give any option to clear vehicle faults, only emissions. It's possible more expensive better featured ones will work but is it worth the money for the once or twice you encounter the cut off issue?

It's a good question and I guess the answer depends on your circumstances. In my case we were 100km north of Seville on Saturday afternoon with nothing around except a hotel and a restaurant. We had a ferry to catch on the Monday. When the fault occurred I tried for a couple of hours to reset by disconnecting the 12v battery with no success. I spoke to international breakdown and they sent someone to tow the car to a depot and look at on Monday. I explained this was too late and eventually got them to leave the car where it was. After the whole family and our dog spending the night in the restaurant storeroom ( the hotel would not take dogs) the breakdown people managed to persuade the BMW technician to come out on Sunday (unheard of in Spain). Managed to reset and get going, and we made the Ferry. If we hadn't got the car going that day we'd have had to pay for hire cars and to repatriate the MG.

So in short, I don't mind paying a bit more for some peace of mind. Otherwise we'll have to get a new car or go back to Diesel if we want to carry on with road holidays.

I was going to try that but carscanner was being so slow to scan the various fault codes It was quicker to disconnect the 12v

In my case disconnecting the 12v battery had no effect, so I'm looking for belt and braces options for peace of mind.

 

[5teep]

I've had it 3 times now, 2 times waiting ten mins fixed it the third I had to get the AA out and their guy did as clear all faults on his obd tablet. That fixed the problem but I had to wait 2 hours for him to get there. Mostly it occurs when you charge past 95%, nowadays I stop about 90% max but normally well before that just because it takes so long.

 

[boomish]

Wow that sounds horrific, glad you got it going, surely this is a warranty thing & should never happen? Were away on holiday at the moment but still in the UK. I’ve only fast charged to 80% but I have seen a HV battery error message before , can’t remember exactly what it said but cars been fine, I’ll remember to keep my OBD in the car in future.
if it helps am about to upgrade to the pro version of car scanner & it’s not that expensive on Apple Store, currently £6.99 forever or £4.49 for the year .

 

[mikedarby]

Wow that sounds horrific, glad you got it going, surely this is a warranty thing & should never happen? Were away on holiday at the moment but still in the UK. I’ve only fast charged to 80% but I have seen a HV battery error message before , can’t remember exactly what it said but cars been fine, I’ll remember to keep my OBD in the car in future.
if it helps am about to upgrade to the pro version of car scanner & it’s not that expensive on Apple Store, currently £6.99 forever or £4.49 for the year .

Indeed, it shouldn't happen. I haven't approached MG about it, but I've seen threads where others have and it seems hard to get MG to accept responsibility. There's also speculation about whether the issue is due to some charger manufacturers' interpretation of the charging communication protocol, so who knows really...

Can I ask which OBD device you use?

 

[boomish]

Indeed, it shouldn't happen. I haven't approached MG about it, but I've seen threads where others have and it seems hard to get MG to accept responsibility. There's also speculation about whether the issue is due to some charger manufacturers' interpretation of the charging communication protocol, so who knows really...

Can I ask which OBD device you use?

I bought 2 generic OBD’s some time ago from Amazon, 1 Bluetooth & 1 Wi-Fi, I often found only 1 would work when communicating to the car. & it’s the same with the MG5 the Wi-Fi works but the Bluetooth doesn’t, it’ll connect but not for long. The Wi-Fi is a little awkward but one you set the ip address up it works every time. My original Amazon Oder won’t show a current page but this is exactly like the one I have.
OBD2 Scanner WiFi Car Engine Fault Code Reader Reset Adapter for iPhone IOS Android Windows, Auto Check Clear Engine Light CAN ODB2 Diagnostic Scan Tool https://amzn.eu/d/j540Y8F

 

[mikedarby]

I bought 2 generic OBD’s some time ago from Amazon, 1 Bluetooth & 1 Wi-Fi, I often found only 1 would work when communicating to the car. & it’s the same with the MG5 the Wi-Fi works but the Bluetooth doesn’t, it’ll connect but not for long. The Wi-Fi is a little awkward but one you set the ip address up it works every time. My original Amazon Oder won’t show a current page but this is exactly like the one I have.
OBD2 Scanner WiFi Car Engine Fault Code Reader Reset Adapter for iPhone IOS Android Windows, Auto Check Clear Engine Light CAN ODB2 Diagnostic Scan Tool https://amzn.eu/d/j540Y8F

Thanks for that, I'll have a good look.

 

[Nielslein]

Hi. I've seen a number of threads where people have experienced an HV battery shutdown following a rapid CCS charge.
We experienced this on a road trip in Spain, and had a something of a nightmare getting going again. We ended up having to stay the night in a restaurant's store room - long story...
I had tried disconnecting the 12v battery many times, waiting anywhere up to 30 mins before trying again. As others have said the only thing that worked was when a (BMW) service engineer arrived and reset everything via OBD. This wasn't straightforward either and in the end neither of us was actually clear why the reset worked.

The car has been fine since, but obviously without knowing exactly what triggered the lock out it's nerve wracking using fast chargers far from home.

My question is does anyone know a particular OBD device and app combo that they have used to successfully reset an HV battery shutdown themselves with a degree of confidence?

Many thanks.

Had the same issue and the car needed to be towed back to the Netherlands where they said the 12 battery (!) had been defect. What is OBD?

 

[dragon2611]

What percentage did you charge to on the rapid charger?
Good to stop at 80% over 90 % may give you issues

But it shouldn't and if it is then it's a bug MG need to fix

OBD is onboard diagnostics, there's a port you can connect a diagnostic computer to, on my RHD model it's near the centre console in the drivers footwell, no idea if the LHD models have it in a different location.

You can buy little Bluetooth or Wi-Fi dongles that plug into this port and then be used with various mobile apps to read various sensors and sometimes clear fault codes (Depends on the dongle/app and the car), it's also usually where the garage will plug in their diagnostic equipment.

You can also get more advanced tools/tablets.etc for this port, but those are quite expensive.

 

[Gomev]

I bought 2 generic OBD’s some time ago from Amazon, 1 Bluetooth & 1 Wi-Fi, I often found only 1 would work when communicating to the car. & it’s the same with the MG5 the Wi-Fi works but the Bluetooth doesn’t, it’ll connect but not for long. The Wi-Fi is a little awkward but one you set the ip address up it works every time. My original Amazon Oder won’t show a current page but this is exactly like the one I have.
OBD2 Scanner WiFi Car Engine Fault Code Reader Reset Adapter for iPhone IOS Android Windows, Auto Check Clear Engine Light CAN ODB2 Diagnostic Scan Tool https://amzn.eu/d/j540Y8F

I had a cheapo OBD for my Gen1 ZS EV and using Car Scanner it worked great.
When I changed to the MG5 the same setup didn't work, I could connect to the dongle but failed everytime to connect to the car ECUs.

So I bought the OBD dongle that you mentioned in your post and exactly the same, connects to the dongle no problem, but cannot find any ECU profiles for the car. I have the paid for Scanner Pro, as it only cost £1.99 when I upgraded from the free one.

Has anybody else got the same problem ? Am I doing something wrong, I don't think so as connection to the dongle is good. Why can't it connect to the ECUs ?

 

[MickeySw]

Hi

My experience with cheap OBD dongles is that some work, others don’t and even two of the same behave differently due to HW/SW differences.

I got an OBD Link LX to work with a different EV a while back, investment paid off as it now also works with the MG5

Mickey

 

[5teep]

The pre facelift MG5 obd interface is not great and info is scarce. In the resource section of the forums there's an app called OVMS and the author has done some work to try and make it suit the MG5.

 

[dragon2611]

The pre facelift MG5 obd interface is not great and info is scarce. In the resource section of the forums there's an app called OVMS and the author has done some work to try and make it suit the MG5.

I don't believe it supports clearing codes, whilst the hardware should be capable the software doesn't have a function for that.

Now if you knew exactly what to send you could possibly do it as a raw OBD message, but you'd really have to know what you were doing to go down that rabbit hole.

 

[boomish]

Not sure if anyone has mentioned this before but I checked my battery health via my OBD dongle the other day & it wouldn’t connect to the ECU but would connect to the ELM (that could be the other way around) . It worked fine last time I used it , then I tried connecting with the car off & connected instantly, then I switched the car on & read the stats.
This is an old OBD wifi model I got from Amazon years ago .
Weirdly I upgraded the Car Scanner Pro app & couldn’t tell the difference & I never found the individual cells health page. Good thing though the battery health SOH is still the same as last time I checked