Downhill -revving engine alarmed at noise

[Marc o Polo]

Thanks Webbah!!

 

[Grand Tourismo]

I have noticed that since pulling my caravan for a few hundred miles the radar operated cruise control (Distronic) has "learned" the new conditions....and even though I am now not towing, it holds much higher revs for longer periods...does anyone know if the Distronic memory can be reset?

 

[Chris]

I wonder if anyone can advise re. the following, please? I’ve noticed that engine revs increase quite audibly when MP is going downhill and wonder if that’s normal for an automatic vehicle (40+ years a driver, but no previous familiarity with automatics until I got the MP!). If it’s a normal phenomenon that’s fine; but if not I’d like to know the cause – in particular if it’s something I’m doing (or not). Most grateful for any suggestions – thanks!

I just picked up my 2021 300d MP 4Matic yesterday and experienced the severe thunk/jolt when downshifting from 2nd to 1st as well. Brought it to service today and they said it is a known issue and are applying the software remap update. Told me it should only be about 30 minutes. Also I mentioned the MBAC was on Generation 1 and not Generation 2. He said this is also a software update and will try and do that one as well today even though I just came by without an appointment. Fingers crossed!

We have the same jolting issue, I thought it might be new brakes bedding in, so appreciate the input.

 

[Chris]

I wonder if anyone can advise re. the following, please? I’ve noticed that engine revs increase quite audibly when MP is going downhill and wonder if that’s normal for an automatic vehicle (40+ years a driver, but no previous familiarity with automatics until I got the MP!). If it’s a normal phenomenon that’s fine; but if not I’d like to know the cause – in particular if it’s something I’m doing (or not). Most grateful for any suggestions – thanks!

We are doing some slopes in Scotland and have experienced similar. I like the vehicle helping on descents. Sometimes she is overly cautious but hitting the accelerator shifts to a higher gear.

 

[The fat controller]

O

I just picked up my 2021 300d MP 4Matic yesterday and experienced the severe thunk/jolt when downshifting from 2nd to 1st as well. Brought it to service today and they said it is a known issue and are applying the software remap update. Told me it should only be about 30 minutes. Also I mentioned the MBAC was on Generation 1 and not Generation 2. He said this is also a software update and will try and do that one as well today even though I just came by without an appointment. Fingers crossed!

Oh to have your experience of dealers... I'm sitting waiting for an update which they've told me will take a few hours or even all day. No talk of known issues here even though I've explained to them what the issue is and that I've spoken to several people who have had it fixed...

 

[Grand Tourismo]

O

Oh to have your experience of dealers... I'm sitting waiting for an update which they've told me will take a few hours or even all day. No talk of known issues here even though I've explained to them what the issue is and that I've spoken to several people who have had it fixed...

And I bet you waited two weeks for appointments and the pleasure of sitting there all day....good luck TFC!

 

[The fat controller]

And I bet you waited two weeks for appointments and the pleasure of sitting there all day....good luck TFC!

2 weeks.... I wish! Closer to 4!!

 

[The fat controller]

... And after a 'quick' diagnosis they have found.... Nothing wrong. Apparently. They will need a full day to have a 'proper' look so have booked in when they have a loan car available. Only another 4 weeks!

Not delighted with my first experience of dealer service.

 

[Webbah]

Mine was occasionally staying in low gears and high revs when I was going down mountain passes and I just used the paddle shifter with one tap on the right one (+) and it upshifted to a higher gear. Automatic mode didn't disengage. That works for me to manage it. And if it is in too high of a gear when I want to pass quickly I just do the opposite with the left paddle (-) to downshift and then let automatic take over again after passing.

 

[The fat controller]

Mine was occasionally staying in low gears and high revs when I was going down mountain passes and I just used the paddle shifter with one tap on the right one (+) and it upshifted to a higher gear. Automatic mode didn't disengage. That works for me to manage it. And if it is in too high of a gear when I want to pass quickly I just do the opposite with the left paddle (-) to downshift and then let automatic take over again after passing.

Thanks for the tip. Didn't realise you could do that.

 

[Simon and Elie]

I wonder if anyone can advise re. the following, please? I’ve noticed that engine revs increase quite audibly when MP is going downhill and wonder if that’s normal for an automatic vehicle (40+ years a driver, but no previous familiarity with automatics until I got the MP!). If it’s a normal phenomenon that’s fine; but if not I’d like to know the cause – in particular if it’s something I’m doing (or not). Most grateful for any suggestions – thanks!

Yeh I have noticed this too and thought it a little abnormal. My last two automatic cars didn’t do this quite as severely, but as others mention it makes sense if the engine can take some of the pressure of the braking system as fully loaded, fuel/water and your gear, I imagine it’s a significant extra weight.

 

[Method7]

My 18 plate MP doesn’t do that, I think the solution is the software update mentioned above. In fact I never notice gear changes up or down, it’s like silk.