2 month old ZS EV LR - several faults and now HV Battery Shut Off

[Gadget Geek]

I suspect I'll have to drive it until it fails again. If it does the same again I'm rejecting no question.

Let the dealership know that in writing and consider using recorded delivery so that you have evidence of the date.

 

[RhythMick]

OK it's been a while but it's a good time to update the forum.

Firstly, the disconnect happened again. I had the AA recover it to Cars2 MG Barnsley without interacting with the fault codes in any way. While being recovered I emailed the MD to report the fault had happened again, to state that this was their final chance to fix under the CRA 2015 legislation and to request a loan car. In fairness the dealer does seem to be taking this seriously now.

Yesterday the service manager called me to say they had pinned it down to a fault code (P11303) which occurred without always causing the HV battery disconnect but which MG Technical said was an precursor. They could see the error occurring. Following the MG guidance they reflashed both the VCU (Vehicle Control Unit) and SCU (Shifter Control Unit) firmware. As of yesterday afternoon the fault code had not been seen again. The service manager asked my permission to use the car for the day.

Today the SM called again to report that the fault code had reoccurred. Working with MG Technical they pinned it down to a faulty accelerator pedal. With the pedal removed from the car they have checked it and found a short to ground. New pedal ordered, replaced and tested by early next week.

I'll keep the forum updated when I get the car back and hopefully it won't happen again. I came within a whisker of engaging the ombudsman - and if it fails again before the 6 months is up (September) I will be doing so.

 

[RhythMick]

For completeness - and I have expressed this strongly to the MD of the dealership - this fault is very dangerous. Without it being fixed I wouldn't drive it again. My wife will take some convincing to get back in the car once its fixed.

When the HV battery disconnects the car suddenly judders to a halt. It's like slamming the brakes on, presumably because the regen kicks in. There just isn't time to react and put the car in neutral. If this happened on the motorway you would be praying the car/coach/HGV behind you had left enough room.

Any car can suffer catastrophic failure of course. The difference here is that the regen kicks in and brings the car quickly to a halt. There's no clutch to quickly disengage and no chance to drift calmly to the hard shoulder.

 

[MG Mile eater]

Since buying my MG ZS EV late February I've had minor faults appear on I would say 3 out of every 4 journeys. They don't stop me using the car but they stop ACC from functioning.

• Auto Emergency Braking System Unavailable
• Pedestrian Auto Emergency Braking Unavailable
• Vehicle Control System Fault

Not very worrying as I say. However today the car shut down completely mid journey with ...

• HV Battery Shut Off

Fortunately the car stopped in a relatively safe place - Christ knows what would happen if that was on a motorway! Several attempts to restart the car failed, taking it through stop, lock, wait, unlock, start (foot firmly on brake). RAC were called out and the guy was able to get it going by ...

• Plug in computer to car port
• Check and clear all faults
• Remove negative terminal from battery
• Wait 10 minutes
• Reattach negative terminal
• Restart car normally

Since the above I haven't had a reoccurence of the minor errors but we'll see what happens over the coming days. The car is booked into my local MG dealer in May to investigate the minor faults. Needless to say this has shaken my confidence in the MG. I hate to imagine my wife using the car by herself on the motorway and the HV battery shutting off, bringing the car to a fault.

Has anyone else had this issue? I will contact the dealer tomorrow and get their advice, but I want to know what caused this and whether it's likely to happen again.

RAC report ...

• Attended vehicle for cut out non restart, RACscan for fault codes, numerous codes recorded, reset codes and performed battery reset, vehicle now goes into ready mode and drives, followed to members home address where they will contact dealership in morning.

Diagnostic codes​

ELECTRO DRIVE

• Name:GEAR SHIFT CONTROL UNIT - SCU
• DTC:U0594-81,Electrical park status

ELECTRO DRIVE

• Name:ELECTRIC VEHICLE COMMUNICATION CONTROLLER - EVCC
• DTC1FF4-1E,Connection confirm (CC) to OBC
• DTC1FF6-1E,Connection confirm (CC) 2 to BMS
• DTC:U2000-04,ECU hardware

ELECTRO DRIVE

• Name:BATTERY MANAGEMENT SYSTEM - BMS
• DTC:U0146-87,Lost Communication With Gateway
• DTC1F10-87,Lost communication with off-board charger module
• DTC1E9B-00,Charging coupler connection status sense value out of range
• DTC1F65-00,On-board charge socket failure hardware

ELECTRO DRIVE

• Name:COMBINED CHARGING UNIT - CCU
• DTC1FC0-03,OBC will stop due to the control pilot (CP) PWM is overtime
• DTC1FC5-96,The temperature sensor in onboard charging socket is faulty

ELECTRO DRIVE

• Name:VEHICLE CONTROL UNIT - VCU
• DTC:U0428-81,Invalid Data Received From Steering Angle Sensor Module (SAS)
• DTC:U18A2-87,BMS_hsc1_frp11(0x2a2) frame timeout
• DTC:U1111-87,Lost communication with battery management system(BMS)
• DTC1BE6-87,BMS module, key message missing
• DTC:U1923-87,Signal invalid for CCU onboard charger plug status
• DTC:U0298-87,Lost communication with high voltage DC/DC module (HVDCDC)
• DTC3042-87,Lost communication with ESS heater
• DTC1B72-00,Torque monitor fault
• DTC1B03-00,Accelerator pedal position sensor, cross check fault
• DTC1B79-29,Inhibited SAS due to data unavailable for FICM
• DTC1B05-12,Accelerator pedal position sensor 2, short circuit to positive

BRAKES

• Name:ANTILOCK BRAKE SYSTEM (ABS)/STABILITY CONTROL SYSTEM (SCS) - ABS/SCS ANTILOCK BRAKE SYSTEM/STABILITY CONTROL SYSTEM/ELECTRIC PARKING BRAKE - ABS/SCS/EPB
• DTC:U0447-81,Invalid data received from gateway (GW)

CHASSIS

• Name:BODY CONTROL MODULE - BCM
• DTC:U1001-87,Lost communication with passive entry & passive start module
• DTC:B1705-96,Lost communication with base station

CENTRAL ELECTRONIC UNIT

• Name:GATEWAY CONTROL MODULE - GW
• DTC:U0245-87,Lost communication with Front infotainment control module (FICM)

TELEMATIC

• Name:TELEMATIC CONTROL MODULE - TBOX
• DTC:B1529-31,Infotainment control module (FICM), communication fault
• DTC:B1533-13,Microphone Input Signal Circuit Open
• DTC:B1534-13,Microphone output, open circuit

SOUND SYSTEM

• Name:FRONT INFOTAINMENT CONTROL MODULE - FICM
• DTC:U1031-87,Lost communication with Infotainment faceplate module (IFP)

AC SYSTEM

• Name:CLIMATE CONTROL - HVAC
• DTC:94C84B,unknown

INSTRUMENT PANEL

• Name:INSTRUMENT CLUSTER - IPK
• DTC:U0245-87,Lost communication with Front infotainment control module (FICM)

DRIVER ASSISTANCE SYSTEM

• Name:FRONTVIEW CAMERA CONTROL MODULE - FVCM
• DTC:U0420-81,Invalid data received from power steering control (EPS) module
• DTC:U130B-81,Invalid data received from front detection radar (FDR)

DRIVER ASSISTANCE SYSTEM

• Name:FRONT DETECTION RADAR - FDR
• DTC:B19C1-81,Adaptive cruise control (ACC) and forward collision warning (FCW) and pedestrian collision warning (PCW) and autonomous emergency braking (AEB) and autonomous emergency braking vulnerable road users (AEB VRU)
• DTC:B19C2-81,Adaptive cruise control (ACC) and autonomous emergency braking (AEB) and autonomous emergency braking vulnerable road users (AEB VRU)
• DTC:B19C3-81,Adaptive cruise control (ACC)
• DTC:B19C4-81,Autonomous emergency braking (AEB) and autonomous emergency braking vulnerable road users (AEB VRU)

DRIVER ASSISTANCE SYSTEM

• Name:AROUND VIEW MONITOR - AVM
• DTC:U0245-87,Lost communication with

Disconnect low voltage battery for 10mins ( 12 volt ) this reset the ECU's
This happens on mine randomly yet to be stranded !

 

[Data]

Yes, this is a slightly

For completeness - and I have expressed this strongly to the MD of the dealership - this fault is very dangerous. Without it being fixed I wouldn't drive it again. My wife will take some convincing to get back in the car once its fixed.

When the HV battery disconnects the car suddenly judders to a halt. It's like slamming the brakes on, presumably because the regen kicks in. There just isn't time to react and put the car in neutral. If this happened on the motorway you would be praying the car/coach/HGV behind you had left enough room.

Any car can suffer catastrophic failure of course. The difference here is that the regen kicks in and brings the car quickly to a halt. There's no clutch to quickly disengage and no chance to drift calmly to the hard shoulder.

Yes, this is a concerning & potentially dangerous fault. Let's hope the accelerator replacement fixes it. Good luck & please do let us all know how you get on.

 

[RhythMick]

Disconnect low voltage battery for 10mins ( 12 volt ) this reset the ECU's
This happens on mine randomly yet to be stranded !

I get that this is an emergency fix.

Surely it's wrong that we just accept this? It's a dangerous fault which we really must not let the manufacturers and dealers get away without fixing.

 

[decrep]

Seems like the dealer did a professional fault find this time. I'd be fairly confident they've got it.

However I agree the fault is unacceptably dangerous!
A HV battery disconnect should engage neutral, not slam the brakes on.

 

[Coulomb]

A HV battery disconnect should engage neutral, not slam the brakes on.

Unfortunately, neutral requires the HV battery to be present. It's not like there is a clutch or multi-speed transmission there to achieve neutral mechanically.

With a permanent magnet motor, neutral is achieved by actively generating a three phase voltage that opposes the permanent magnet. It's not clear to me where the regen power goes when the battery isn't present. I think that the motor controller could be in danger of damage. Perhaps also the air conditoner controller and Combined Charging Unit.

You really need the HV battery to be rock solid. It's an interesting technical problem. Not so interesting for the owners obviously.

I hope I got the above details correct. It's on the edge of my knowledge.

 

[RhythMick]

Unfortunately, neutral requires the HV battery to be present. It's not like there is a clutch or multi-speed transmission there to achieve neutral mechanically.

With a permanent magnet motor, neutral is achieved by actively generating a three phase voltage that opposes the permanent magnet. It's not clear to me where the regen power goes when the battery isn't present. I think that the motor controller could be in danger of damage. Perhaps also the air conditoner controller and Combined Charging Unit.

You really need the HV battery to be rock solid. It's an interesting technical problem. Not so interesting for the owners obviously.

I hope I got the above details correct. It's on the edge of my knowledge.

After the disconnect I was able to engage neutral to push the car to the side of the road.

The manual states that the car should not be jump started as it could damage (something). Clearly that refers to it being in Drive.

I really think this is a problem which the industry needs to standardise an approach on. Someone is going to get killed by a HGV driving too close behind an EV suffering a disconnect.

 

[decrep]

Maybe a clutch is the answer??

 

[Willie]

If they can't get it fixed quickly, what are my rights in terms of courtesy car?

If I were you I would be tempted to call it a day and return the vehicle to the dealership for a full refund