SE SR failing to pre-heat while plugged in

Rolfe

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MG4 SE SR
I know we've had this issue in the past, but it was supposed to have been fixed with a software update. I got that update in April of last year, and I'm realising I still have a problem. I've not heard anyone else complain about this.

Back in 2023, before the update, if I tried to pre-heat the car using the app when it was plugged in but not charging, the instruction always failed. There was no ambiguity about it, I never got as far as the screen showing the HVAC system activated. Then in April I got the update and I thought it was fixed. I activated the pre-heat while the car was plugged in and it all went through. HVAC showing toasty air circulating. But, the car wasn't actually warm. Rather stupidly I ascribed this to the fact that I was using a granny charger, and thought that wasn't capable of delivering enough power to heat the car properly. I thought it would all be fine once I'd got my home charger, which I did in May. May, you know, the month when you generally stop needing to pre-heat.

What with one thing and another, I didn't realise the feature still wasn't working until quite recently. One thing was that it was only on a minority of occasions that I wanted to pre-heat while the car was plugged in. If it wasn't plugged in it was fine, as it always had been, which lulled me into a false sense of security. Another was that at least once it actually seemed to work. In retrospect that may have been because the car was actually charging at the time - I'd just heated the battery (the battery pre-heat function seems to be working fine), and the car was recharging to get back to 100% after doing that.

It took one or two more "what happened this car isn't actually warm" incidents before the penny dropped. It's still doing exactly what it did on the granny charger last April. I set it to pre-heat and the app says it's doing it. The car lights come on as usual. If I walk up to the car I can hear the A/C chirping. If I get into the car I can hear and feel the fan operating, but the fan is only doing about half speed and there isn't any actual heat coming out of the vents. The % charge doesn't drop, whereas when it's working that will drop by 2% when it's pre-heating.

Any thoughts? Anybody else noticed this? I've taken to running out to the garage before breakfast, unplugging the car and moving it on to the driveway ready to go, then going back inside to finish breakfast and getting ready. That way I know that if I set it to heat it will do it. But that's the rigmarole that software update was supposed to elminate.
 
Is the charger active? Is the battery fully balanced?

When I opened the car today after work, it was equalising the battery. I only opened the drivers door so not to interrupt the process.

The HVAC came on, but no heat from the vents even after 10 minutes. Battery power as reported by OBD2 and in car screen was same as if the HVAC was off.

I think in that instance it’s using the 12V battery but conserves energy?

More testing needed.

Preheating at any other level of charge, even if the charging had been stopped, works.

At 100% it works if the charger is still ‘active’ (I use a car park ‘public’ pod-point at ‘home’)

Only when balancing it seems not to work so far.
 
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On my Trophy, if plugged (charging or not) then I don't get any HVAC at all. I have just tried it now as I am about to go off to work.
 
I also wrote here about the problem when the vehicle does not switch on the heater and the vehicle does not heat. And it doesn't matter if the vehicle is charging from the charger or disconnected. It only happens sometimes. No one in the service department knows why the vehicle is not heating and can't fix it. I have an R46.
 
And what should I do if I can't fix it and the diagnostics doesn't see the fault? I need a car to use and not to take it to a garage for 1 month.
 
The first thing you normally do is to write a formal complaint. This contains a clear description of the problem and your warranty claim to get it fixed. Also, you must specify a timeframe to allow the to fix it.
If it means you should leave the car behind, demand compensation (like a car on loan). Send it to the MG CZ and your dealer. See to it that you get notified by if they received it. Send it in by email as well to both.

If you have an insurance covering these things, let a lawyer do this. It really eases of the burden (although lawyers can also be contra productive..).

If they do not respond and ignore you, find out if there is consumer commission that helps judging you in these things. In my country if there is verdict from such a commission, it is binding.
 
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Is the charger active? Is the battery fully balanced?

When I opened the car today after work, it was equalising the battery. I only opened the drivers door so not to interrupt the process.

The HVAC came on, but no heat from the vents even after 10 minutes. Battery power as reported by OBD2 and in car screen was same as if the HVAC was off.

I think in that instance it’s using the 12V battery but conserves energy?

More testing needed.

Preheating at any other level of charge, even if the charging had been stopped, works.

At 100% it works if the charger is still ‘active’ (I use a car park ‘public’ pod-point at ‘home’)

Only when balancing it seems not to work so far.

No, the car had finished balancing.

That's interesting that some other people are having a problem. I'd like to know if it works correctly for others.
 
Mine works when charging is complete. Usually, the charging has ended hours ago before preheating the car. However, after heating the car does not start charging automatically. That would have been nice in case I need to start it twice since it takes away about 2-3 KWh from the battery at - 5°C. Simply upping the charge % in the app and then lower it back to the intended % and the car charges again.
 
Not had any issues with my XPower pre conditioning when plugged in (not charging). Both the heated seats and HVAC function from the app. I have had the app report unsuccessful but the car lights up like a Christmas Tree and the HVAC is on.

Never tried to pre condition while car is charging.

Car is on R40 infotainment software and probably all other software from Sep/Oct 2023 (never been updated)
 
My scheduled battery heating seems to work fine, and I've seen the car recharge itself afterwards, when the time was still within the Zappi's scheduled charge period. So it can do it. Just not for the cabin heating.
 
Is the charger active? Is the battery fully balanced?

When I opened the car today after work, it was equalising the battery. I only opened the drivers door so not to interrupt the process.

The HVAC came on, but no heat from the vents even after 10 minutes. Battery power as reported by OBD2 and in car screen was same as if the HVAC was off.

I think in that instance it’s using the 12V battery but conserves energy?

More testing needed.

Preheating at any other level of charge, even if the charging had been stopped, works.

At 100% it works if the charger is still ‘active’ (I use a car park ‘public’ pod-point at ‘home’)

Only when balancing it seems not to work so far.
Purely a guess, but maybe the HV battery needs to be totally idle while balancing so the cell voltages are virtually static and hence the measured voltages are as accurate as possible ?
 
I'm not able to recheck on mine at the moment (for obvious reasons), but last time I tried this it worked. (Charge point was in the Waiting state, so plugged in but not charging)..
 
And what should I do if I can't fix it and the diagnostics doesn't see the fault? I need a car to use and not to take it to a garage for 1 month.
Annecdotally speaking, this is due to some modules being not up to date, it got solved eventually after basically upgrading everything with SIPS. I'm inclined to point the finger at the TBOX module but I have no way of confiriming that
 
I know the thread is about the SE SR but I thought I would test my Gen 1 Trophy. After charging and balancing to 90% this forenoon I switched on the cabin heating from the App. Initial temperature 8°, Final temperature 19° and battery dropped to 89%. Cable still connected but charging did not restart.
 
This may be a really silly question but have you checked the temp setting via the app ?
Afaik it retains the last setting so if you had it at 21 degrees and it's arctic outside then it won't heat the cabin beyond 21 degrees
 
My 2022 SE is the same, will not preheat if plugged in and fully charged. Works fine if it’s below 100%. Baffling but then so is the useless keyless go on the app that’s never worked either. No software update seems to fix it and I’ve given up asking.
 
This may be a really silly question but have you checked the temp setting via the app ?
Afaik it retains the last setting so if you had it at 21 degrees and it's arctic outside then it won't heat the cabin beyond 21 degrees
If I set it to heat the car, the temperature in the app is updated direcly.
 
Mine works fine, and I have a Zappi, so it’s definitely not to do with your charge point. I know for a fact it still works for me as I’ve used it 2 or 3 times in the past couple of weeks, and it worked every time.
 

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