MG ZS HYBRID+ Gets Fix After Acceleration Issue Exposed by CarSauce

MG Australia has announced a software update for the 2025 MG ZS HYBRID+ after independent testing by CarSauce revealed a significant discrepancy in the vehicle’s acceleration performance under specific conditions. During CarSauce’s testing, the ZS HYBRID+ recorded a 0–100km/h time of 24.59 seconds when the 1.83kWh battery's state of charge (SOC) was depleted.

This performance fell well short of MG's official claimed time of 8.7 seconds. However, once charge was restored to the hybrid system through regenerative braking, the ZS HYBRID+ completed the same sprint in 8.04 seconds, surpassing the manufacturer’s claimed figure.


This disparity highlights a limitation in the vehicle's hybrid system, where power delivery becomes heavily reliant on the battery’s charge level. While the hybrid system is designed to blend the outputs of its 1.5-litre four-cylinder engine and 100kW electric motor for a total output of 158kW, the depleted SOC appeared to reduce the system's ability to deliver consistent performance.

Such variability could pose challenges in real-world scenarios, particularly during overtaking or merging, where acceleration needs to be predictable and responsive.

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All article: mg-zs-hybrid-gets-fix-after-acceleration-issue-exposed-by-carsauce

 

[mickel]

Just picked my car up from MG Shrewsbury.
The chap I spoke to said the technician had applied an update to the PEU and all my other software was already updated.
He could not confirm if the update was PD052.
He said they had test driven the car but couldn't recreate the over-revving issue.
His only suggestion was for me to video the over-revving, which isn't going to be easy when I'm driving, but I'll give it a go.
They refused to look at the comments and issues raised on this forum.
Any advice is welcome.

Sound pretty clueless to me. Refused to look at comments and issues raised in this forum!!! Unbelievable. Can you not ask for a print out of all updates applied to the car? Thought they might have given you anyway? Obviously not.

 

[Nico]

I did ask for a print out but was told it wasn't available today and to call tomorrow.
I have just written a long email to the dealer outlining all the issues with my car - excess revving, loss of power uphill and overtaking, squealing brakes, lane assist pulling me over the centre line.
My dealer did say a month ago that MG UK recognised the over-revving issue and had released the updates to her.
I have asked for confirmation of what the PEU update actually resolved and whether PD052 has or will be applied.
I have also stated I may need to return the car under the Sale of Goods Act 1979 if all issues are not resolved quickly.

 

[mickel]

I did ask for a print out but was told it wasn't available today and to call tomorrow.
I have just written a long email to the dealer outlining all the issues with my car - excess revving, loss of power uphill and overtaking, squealing brakes, lane assist pulling me over the centre line.
My dealer did say a month ago that MG UK recognised the over-revving issue and had released the updates to her.
I have asked for confirmation of what the PEU update actually resolved and whether PD052 has or will be applied.
I have also stated I may need to return the car under the Sale of Goods Act 1979 if all issues are not resolved quickly.

The entire update procedures seems rather complicated and open to potential confusion. Seems overly complicated to apply updates to the car that solve issues without creating other potential issues.

 

[Ken K]

I called my dealer this afternoon and explained the problem, was put through to a software specialist who after listening to the issue booked the car in for the update. I mentioned PD052 and EMC PEU TCM and she seemed to be aware of them. I'll let you know the results but it won't be until April as that's the earliest I can take it in due to previous commitments.

 

[Nico]

Further to my previous posts where I'd hoped the PD052 update had been applied to my car.
I drove the car home today from Shrewsbury (50 miles). On several occasions the car over-revved on long but not steep upslopes.
It can't be that the battery has depleted as some seem to suggest as at the top of a couple of upslopes the car immediately kicked into EV mode.
Still awaiting a response from the dealer.

 

[diwat123]

Further to my previous posts where I'd hoped the PD052 update had been applied to my car.
I drove the car home today from Shrewsbury (50 miles). On several occasions the car over-revved on long but not steep upslopes.
It can't be that the battery has depleted as some seem to suggest as at the top of a couple of upslopes the car immediately kicked into EV mode.
Still awaiting a response from the dealer.

What do you mean by over-reving?

 

[Nico]

What do you mean by over-reving?

As I drive uphill I lightly press the accelerator to maintain my speed and revs rise from about 2000 to 3000+ and on occasion 5000+. The increase is very audible and there is no acceleration. It's like being out of gear in a manual car. I have to take my foot off the accelerator, slow down and let the revs drop before it seems to find gear and settle down.

 

[diwat123]

Then this is not over-revving. In my opinion, 3,000 RPM is perfectly fine. If you're driving uphill for an extended period or encountering repeated inclines before the battery has had a chance to recharge, then even 5,000 RPM is acceptable.

At lower speeds (below 45 mph), the electric motor powers the drivetrain. If the battery is depleted, the car needs to recharge it, which causes the engine revs to increase. Even after reaching the top of a hill, the revs may remain elevated until the battery is sufficiently charged—at which point they should drop. This doesn't mean the car is "slipping" the clutch; the higher revs aren’t for acceleration but for battery recharging. What you're experiencing is normal behaviour.

Slowing down slightly doesn’t "fix a problem" because there is no problem. Reducing speed lowers battery consumption, so the engine requires fewer revs to recharge the battery while driving.

The setup in MG is quite different from a conventional internal combustion engine and even from other hybrids due to its powerful electric motor and driving it maybe needs a bit more to get used to. Or you can just not overthink it's behaviour and let the car do its thing.

 

[Nico]

3000 revs would be fine as you say but not if the car loses its acceleration every time - which happened once when I was overtaking and was frightening and downright dangerous.
And, as I said earlier the battery clearly wasn't depleted or in need of extra recharge as it switched to EV as I reached the summit.
If I overtake and let the car "do its thing" someone could be seriously hurt.

 

[diwat123]

If car loses the power - then it is bad and something could be wrong. You did not mention it in the previous post or I misunderstood it.

Switching to EV on summit - does not prove that the car did not need the recharge or the battery was depleted. Once the recharge process started - it lasts for some time. But when the energy needed to drive the car drops instantly when reaching the summit - the car can go int EV mode directly.

 

[Nico]

My last but one post did say "The increase is very audible and there is no acceleration".
I note your comments regarding the battery but others on the forum I believe had suggested a link between depleted battery and over-revving. This doesn't seem to be the case in my experience.
The excessive revving and deceleration occurs say 3/4 of the way up a hill whilst the battery seems to still have good charge. Less than two minutes later, at the summit, it's in EV mode.

 

[diwat123]

I understood that you expected acceleration because of the car revving, not that it reved and had no acceleration.

How long is the way uphill? How high is the incline? Could you give the specific location on Google Maps to check this? I am wondering if the inclines that I have passed are similar to yours - maybe I did not experience revving or power loss because the hills were just shorter or more flat?

 

[AlexB1988]

Hi also just to add, 5000rpm at any consistent level is bad for the engine at any point, particularly a new car. In fact the user manual on page 137 states this:

Running-in The engine, transmission, brakes and tyres need time to "bed-in" and adjust to the demands of everyday motoring. During the first 900 miles ( 1500 km) , it is essential that you drive with consideration for the running-in process and heed the following advice: • Do not allow the engine to exceed 3000 rpm in any gear or the vehicle speed to exceed 75 mph ( 120 km