qualified mechanic needed

[Mighty Mouse]

somethings gone wrong with the MG ZS. went to drive into town tonight,
and the car accelerated normally until it got to 40 klmph, then it
stayed at that speed. it wouldn't go any faster. the accelerator had no
more effect. the speedo needle stayed rock steady on 40 klmph no matter
how hard I pressed the accelerator. It was hot today, over 30 degrees I
think, but there were no warning lights on the dash. any ideas before I
contact the dealer?

[Clocky]

Post by Mighty Mouse
somethings gone wrong with the MG ZS. went to drive into town tonight,
and the car accelerated normally until it got to 40 klmph, then it
stayed at that speed. it wouldn't go any faster. the accelerator had no
more effect. the speedo needle stayed rock steady on 40 klmph no matter
how hard I pressed the accelerator. It was hot today, over 30 degrees I
think, but there were no warning lights on the dash. any ideas before I
contact the dealer?

That could be indicative of going into limp home mode. No engine lights
on and did it drive normally after after cooling down and/or cycling the
ignition?

It could be anything from an O2 sensor to something more serious but
really your best bet is to contact your dealer and have them look at it.
It is under warranty so...

[Mighty Mouse]

Post by Clocky

Post by Mighty Mouse
somethings gone wrong with the MG ZS. went to drive into town
tonight, and the car accelerated normally until it got to 40 klmph,
then it stayed at that speed. it wouldn't go any faster. the
accelerator had no more effect. the speedo needle stayed rock steady
on 40 klmph no matter how hard I pressed the accelerator. It was hot
today, over 30 degrees I think, but there were no warning lights on
the dash. any ideas before I contact the dealer?

That could be indicative of going into limp home mode. No engine
lights on and did it drive normally after after cooling down and/or
cycling the ignition?

I haven't tried it since I drove home. I will try it tomorrow, and ring
the dealer

Post by Clocky
It could be anything from an O2 sensor to something more serious but
really your best bet is to contact your dealer and have them look at it.
It is under warranty so...

[Xeno]

Post by Mighty Mouse
somethings gone wrong with the MG ZS. went to drive into town tonight,
and the car accelerated normally until it got to 40 klmph, then it
stayed at that speed. it wouldn't go any faster. the accelerator had no
more effect. the speedo needle stayed rock steady on 40 klmph no matter
how hard I pressed the accelerator. It was hot today, over 30 degrees I
think, but there were no warning lights on the dash. any ideas before I
contact the dealer?

As Clocky said, it seems to be limp mode. It's a safety feature that
allows the car to be driven home albeit at a low speed/power. Often it
will only allow 1 transmission speed. Did your MG clear itself once you
got home and cycled the ignition?

If now warnings came up, that would be strange. A code reader would be
handy, or a scantool. I'd check that the battery voltage is OK. Should
be >12.6 measured at the battery. Most cars these days have a battery
voltage sensor on one of the terminals. If it is faulty or has a bad
connection, strange things can happen.

Anyway, they have, IIRC, a 7 year warranty - go test it out.

[Mighty Mouse]

Post by Xeno

Post by Mighty Mouse
somethings gone wrong with the MG ZS. went to drive into town
tonight, and the car accelerated normally until it got to 40 klmph,
then it stayed at that speed. it wouldn't go any faster. the
accelerator had no more effect. the speedo needle stayed rock steady
on 40 klmph no matter how hard I pressed the accelerator. It was hot
today, over 30 degrees I think, but there were no warning lights on
the dash. any ideas before I contact the dealer?

As Clocky said, it seems to be limp mode. It's a safety feature that
allows the car to be driven home albeit at a low speed/power. Often it
will only allow 1 transmission speed. Did your MG clear itself once
you got home and cycled the ignition?

haven't tried

Post by Xeno
If now warnings came up, that would be strange. A code reader would be
handy, or a scantool. I'd check that the battery voltage is OK. Should
be >12.6 measured at the battery.

just went and checked it. 12.8 volt

Post by Xeno
Most cars these days have a battery voltage sensor on one of the
terminals. If it is faulty or has a bad connection, strange things can
happen.

can't see anything on either terminal

Post by Xeno
Anyway, they have, IIRC, a 7 year warranty - go test it out.

yep. I'll ring the dealer tomorrow and see what they have to say. I'd
never heard of limp mode.

[Xeno]

Post by Mighty Mouse

Post by Xeno

Post by Mighty Mouse
somethings gone wrong with the MG ZS. went to drive into town
tonight, and the car accelerated normally until it got to 40 klmph,
then it stayed at that speed. it wouldn't go any faster. the
accelerator had no more effect. the speedo needle stayed rock steady
on 40 klmph no matter how hard I pressed the accelerator. It was hot
today, over 30 degrees I think, but there were no warning lights on
the dash. any ideas before I contact the dealer?

As Clocky said, it seems to be limp mode. It's a safety feature that
allows the car to be driven home albeit at a low speed/power. Often it
will only allow 1 transmission speed. Did your MG clear itself once
you got home and cycled the ignition?

haven't tried

Post by Xeno
If now warnings came up, that would be strange. A code reader would be
handy, or a scantool. I'd check that the battery voltage is OK. Should
be >12.6 measured at the battery.

just went and checked it. 12.8 volt

Yeah, that's healthy enough.

Post by Mighty Mouse

Post by Xeno
Most cars these days have a battery voltage sensor on one of the
terminals. If it is faulty or has a bad connection, strange things can
happen.

can't see anything on either terminal

Like this;

https://www.bosch-mobility.com/en/solutions/sensors/electronic-battery-sensor

On the earth terminal. If the charge system is computer controlled,
you'll have one.

Post by Mighty Mouse

Post by Xeno
Anyway, they have, IIRC, a 7 year warranty - go test it out.

yep. I'll ring the dealer tomorrow and see what they have to say. I'd
never heard of limp mode.

https://obd2australia.com.au/car-in-limp-mode/


____
Xeno

Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)