Newly purchased MG5 battery module fault

[triharder]

I collected a brand new MG5 from a dealer 3 weeks ago. I was assured that the 12v battery symbol being red would disappear after being driven for a bit. The car seemed to behave normally, so I set off.
10 miles down the road, the red battery symbol was still red and the dash flashed up tens of failure errors. The car surged and decelerated madly and eventually simply shut down , coasting to a halt. Zero power to any devices, except for hazards, but the doors could be opened. On relaying the car back to the dealership, they analysed the fault claiming a failed software update and later admitted that the multi charge unit needed replacing. I still get the HD battery shutoff message occasionally- despite foot on pedal!
Often occurs when the ignition light is green and I've been eg route planning for a few minutes. MG has been unable to diagnose this issue. The same used to occur on my previous MG5...

 

[Jomarkh]

What voltage was the dash saying the 12v battery was at?
Mine shows around 14v in ready mode.

 

[MickeySw]

I still get the HD battery shutoff message occasionally- despite foot on pedal!
Often occurs when the ignition light is green and I've been eg route planning for a few minutes. MG has been unable to diagnose this issue. The same used to occur on my previous MG5...

Logic would indicate that if you have the exact same same issue with two different cars then you must be the cause of it as the only common denominator??


Joking aside, it may be a good idea to invest in an OBD dongle/app to read out DTCs the next time this happens and present the dealer with the fault codes?

 

[triharder]

What voltage was the dash saying the 12v battery was at?
Mine shows around 14v in ready mode.

It didn't show a voltage just a red battery symbol

 

[triharder]

Logic would indicate that if you have the exact same same issue with two different cars then you must be the cause of it as the only common denominator??


Joking aside, it may be a good idea to invest in an OBD dongle/app to read out DTCs the next time this happens and present the dealer with the fault codes?

Where is the OBD socket location on the MG5?

 

[Alb]

Under the dash to the left of the steering column.

 

[MickeySw]

It didn't show a voltage just a red battery symbol

The FL model has a 12V screen that shows voltage and SoC.

Press > on the steering wheel until the car symbol shows on the dash, then use up/down to scroll trough the various sub screens

I was assured that the 12v battery symbol being red would disappear after being driven for a bit.

There is no alternator in an EV, as soon as the car is READY the 12V aux is charged by the HV Battery via the CCU, no need to drive..

The On relaying the car back to the dealership, they analysed the fault claiming a failed software update and later admitted that the multi charge unit needed replacing.

I’d say given the antics mentioned above they never replaced the 12V aux battery, merely jump started it to get you off their forecourt.

Best to avoid the dealer and replace it with a branded aftermarket car battery.

 

[Gomev]

..
Often occurs when the ignition light is green and I've been eg route planning for a few minutes. MG has been unable to diagnose this issue. The same used to occur on my previous MG5...

When you say the ignition light is green, is that on the start/stop button? Is the car in Ready mode, you don't mention that ? If you just press the 'ignition'/start stop button twice the light on it is green but car is not Ready and so will be discharging the 12V rapidly and is not really recommended.

 

[MickH]

A quick update , the car was collected by the AA and taken to the nearest MG dealer. They have diagnosed the steering column lock module as the fault. Part has been ordered and should be fitted Tuesday/Wednesday and hopefully that will be it!!
I'll update once the work is complete

so has this been resolved??

 

[triharder]

When you say the ignition light is green, is that on the start/stop button. ? Is the car in Ready mode, you don't mention that ? If you just press the 'ignition'/start stop button twice the light on it is green but car is not Ready and so will be discharging the 12v rapidly and is not really recommended.

Car goes directly into ready mode with foot on brake. If foot not on brake then it's amber before green. Sometimes when in ready mode, I'll have fan on to clear screen etc and then try to go into drive but fails to engage AND often there is no warning message eg HD Battery shutoff.

 

[Gomev]

Car goes directly into ready mode with foot on brake. If foot not on brake then it's amber before green. Sometimes when in ready mode, I'll have fan on to clear screen etc and then try to go into drive but fails to engage AND often there is no warning message eg HD Battery shutoff.

In which case I tend to agree with @MickeySw in post #27 in this thread