Automatic jerking

[ferasalhafar]

Hi all,

I don't know if it is a problem or not. When I'm driving on third gear, if I slow down, for instance to turn right or left (the rev counter goes right down) and when I want to accelerate again while the engine is changing the gear from third to second, the car jerks a bit. Is that normal?

My car is C Class 2009 Auto


Thanks

 

[coventryslk]

that happened to me when i woke up this morning

 

[ferasalhafar]

I hope you enjoyed it!

 

[ferasalhafar]

Can anyone advise please, should I book it in with MB or is that normal to happen when it is bad timing accelerating while the gear is being changed from 3 to 2.

No jerking!! I mean no jokes about jerking!!

 

[Naraic]

Hi all,

I don't know if it is a problem or not. When I'm driving on third gear, if I slow down, for instance to turn right or left (the rev counter goes right down) and when I want to accelerate again while the engine is changing the gear from third to second, the car jerks a bit. Is that normal?

My car is C Class 2009 Auto


Thanks

No, its not normal. The car is young...get the codes read.

 

[ferasalhafar]

No, its not normal. The car is young...get the codes read.

Thanks for your reply. Can they read the codes even if I can't see any messages or faults light on?

Thanks

 

[Naraic]

I think so.

 

[mercdriver25]

Hi,

Certainly doesn't seem normal.

However, having said that, I drove a mate's S500 auto a couple of weeks ago, and that did something very similar....it was always when slowing down, and speeding up again - almost felt like as though the auto 'box was getting confused... He said the dealers were going to sort it.

So I agree...get the codes read..

 

[ferasalhafar]

I will do, thank you.

 

[dieselman]

If this car is fitted with a 7G gearbox, it tends to be a characteristic trait.

 

[ferasalhafar]

If this car is fitted with a 7G gearbox, it tends to be a characteristic trait.

It's 5 gears Auto. Today I was driving the whole day and it didn't do it once!

 

[television]

These gearboxes do have a small memory that can leave codes, not a normal fault for the 722.6 box

 

[ferasalhafar]

These gearboxes do have a small memory that can leave codes, not a normal fault for the 722.6 box

Thanks for your comment. The strange thing is that most of the time it is fine. Only maybe one out of a thousand times it happens that when I accelerate while the engine is changing gears, the car kind of jumps. It feels as if you are driving a manual car and it is like you lifted your foot off the clutch quickly.

If you leave it driving on third gear without accelerating, eventually it changes to second and you don't feel it.

I don't want to waste one day by booking it in with MB unneccesarily, or do you think it is better to have it checked?

Thanks

 

[ferasalhafar]

I booked the car in with MB. They didn't find any fault codes but decided to update the
ECU software. They did, but the car now drives off on the first gear not on the second gear when in C mode. The technician tried to convince me that it is the new software and that's the way it is! I said to him I'm not happy with that because I often drive the car in C mode especially in snow and ice and I asked him to get it back to how it was before. He said he will speak to the technical team of MB and clarify with them if they can get it back to how it was before or does the new software mean that all cars will be the same as mine from now on. This means that I might not have the C mode function anymore!
Does anyone have any advice please?

 

[television]

What ever has the guy done, the C mode is electrically switched

 

[ferasalhafar]

What ever has the guy done, the C mode is electrically switched

When it is switched on, you see it in the dashboard ''C'' but the car still drives off in first gear.

 

[kole301]

Check engine and transmission mounts...
Level of ATF also...

 

[wireman]

Also check the prop shaft couplings and rear subframe & diff mounts.

Perhaps a fluid & filter change is due

 

[ernieh]

W204; C / S Starts?

There have been a few discussions on this in the past......My 204 definitely starts in first no matter which mode is selected. The difference is mainly in the change-up / change-down points for given driving conditions and believe me, this is no help whatsoever in the current snowy weather conditions!

My previous car, a W203 started in second when C was selected and was much less likely to get stuck in the snow. I might be wrong, but your man might struggle to get a 204 to start in second when in C!

Let us know the outcome, because a few of us might be looking to have the update carried out if it helps in poor conditions.


Ernie

 

[ferasalhafar]

There have been a few discussions on this in the past......My 204 definitely starts in first no matter which mode is selected. The difference is mainly in the change-up / change-down points for given driving conditions and believe me, this is no help whatsoever in the current snowy weather conditions!

My previous car, a W203 started in second when C was selected and was much less likely to get stuck in the snow. I might be wrong, but your man might struggle to get a 204 to start in second when in C!

Let us know the outcome, because a few of us might be looking to have the update carried out if it helps in poor conditions.


Ernie

Thanks for your reply. Before yesterday I was always driving it in C mode and it always drives off on second gear. Strange yours doesn't...

I rang two other dealers and spoke to the STM (service team manager) ;

The first STM said '' it is in learning mode and it will learn by time to drive off on the second gear''. I think that is rubbish!!

The second STM said that, he upgraded lots of softwares and never experienced this before, he insisted that the car should drive off on second gear in C mode. He advised me to keep the booking on friday and see what can they do.

My car already doing 20 MPG,and now it will even spend more petrol driving off on first gear

I will update on friday.