7g Auto Not Smooth Anymore. E280 cdi sport

[mystic.bertie]

When i got my car a couple of months ago the 7g auto gearbox seemed smooth enough. Because of my occasional limp mode problem i was doing a lot of thrashing about trying to repeat the fault, i have stopped the thrashing about now. When i pull away at work in C mode, im faced right away with a speed hump and if i take my foot off, the car dives as if its in 1st gear, i read sport mode uses 1st for pulling away and comfort 2nd gear. Also gear changes are not as smooth. If i floor it in C mode the gear changes at 4000 revs just like sport mode.

Guys is there a reset for this?

 

[Stardelta]

Hi...carry out the following-

1. Turn the ignition key to the on (not start) position.

2. Press the gas pedal to the floor and hold for five seconds.

3. Turn the key to the "off" position (don't remove the key), then release the gas pedal.

4. Wait at least two minutes for ECU to reset.

Hope this helps

 

[Stardelta]

When it says push the pedal to the floor, it means all the way including the last click for kick down and I always extend the 5 seconds to 10 seconds

 

[whitenemesis]

The only way to reset the TCM adaptions is via STAR.

Just drive as normal and after a few miles the box will re-adapt to your usual driving style.

 

[streethawk]

When i got my car a couple of months ago the 7g auto gearbox seemed smooth enough. Because of my occasional limp mode problem i was doing a lot of thrashing about trying to repeat the fault, i have stopped the thrashing about now. When i pull away at work in C mode, im faced right away with a speed hump and if i take my foot off, the car dives as if its in 1st gear, i read sport mode uses 1st for pulling away and comfort 2nd gear. Also gear changes are not as smooth. If i floor it in C mode the gear changes at 4000 revs just like sport mode.

Guys is there a reset for this?

And keep her in s Ohhh I've only tried in c once for 5 mins in nearly 19 months . She needs S.

 

[GordonTarling]

In view of the age of your car, I'd suggest an ATF change could be in order.

 

[mystic.bertie]

thanks for all the replies, i did the reset procedure and this worked a treat, now the gear changes are smoother and around 1600 rpm when driving smoothly.

Does comfort mode use 1st gear as im still finding it changes down to 1st gear when i go less that 10mph for a speed hump, the engine braking and use of first gear does not feel very smooth ie it braking effect.

It is due a gearbox service but im waiting to see if its worth keeping, my intermittent 'limp mode' fault is bugging me to the point i might not want to keep it, i bought it about 10 weeks ago. So i dont want to splash out too much at the moment, i already spent £250 fixing the suspension and then another £63 on glow plugs. Fair enough if im keeping it but at the moment im not so sure.

 

[Stardelta]

Glad the reset worked for you as it did for me, mine wasn't that smooth in the lower gears at slower speeds but the reset really improved things

 

[rorf]

No where do you mention the vehicles mileage - but for sure a 2007 car should have it's ATF filter and oil changed if it has never been done before.

 

[zipdip]

I followed the ECU reset,this morning like many with the 722.9 box I was getting no faults but the gear change was not quiet right and accelerating on a slip to join a major road had the car doing 3/4 thousand revs before changing in C mode,this has come on very gradually I think for many it just creeps up on you,so I did the reset and went for a short drive what a difference,will give it a longer run tomorrow

 

[fabes]

Just to add to this, did the reset on my Clk last week and it might be placebo, but it seems and feels better / smoother.
Both mooching on the Commute and decent/ spirited run to Bournemouth during the week

Ps Atf change was done 3 months ago aswell

 

[zipdip]

Well I agree I suppose it could be imagination ,one thing that did happen as I started the car after the ECU reset the car started and ran rough,I reversed out the drive and within 200 yards all was well,scared me when it happened,but my car is running better,if it had not been bank holiday monday I would have gone for a decent run,just too much traffic and sunday drivers out there.

 

[zipdip]

Well gave it a thrash this morning ,the gearbox was great changed at the right revs,no knock when cold and needing to stop,did a high speed run,and then did about 4 miles of 30mph which my car was caught between gears,it just gave little jerks at that speed,today nothing it was great

 

[KeithJG]

As some have said there can be a reset procedure but as soon as you drive sedately again the box will adapt and do it`s own thing!....because it is adaptive.

If you look at your car handbook Mercedes recommend to use S Mode as the normal driving mode and yes, it pulls away in 1st gear whatever you do but in C Mode they say it pulls away in 2nd but if you floor it it from stationary it pulls away in 1st gear!......just the same as S Mode.

If you are not so aggressive then although in S Mode it will change at lower revs through the gears due to less load and throttle position.

Perhaps this is why MB say use S Mode for normal driving?

 

[mystic.bertie]

Its good to hear that many are finding an improvement after the reset.

Everything i have read still seems to say that comfort mode should pull away in second gear, if im stationary and press the mode button to manual, it indicates on the dash its in 1st gear.

The changes are much better but still i feel like its in too low a gear when i lift my foot off for a speed hump, rather than keeping the same momentum and rolling over the hump, it still slows the car down as if its in too low a gear.

 

[PobodY]

Probably better to think of it as "cold" mode rather than "comfort". - Wasn't that the original designation ("winter" and "summer" modes)?

 

[whitenemesis]

A cold start will be a first gear pull away to help keep revs up and quickly warm the cats

 

[PobodY]

I thought the idea was to start in second gear and reduce wheelspin in the snow.

 

[mystic.bertie]

It pulls away in 1st even if its warm.

 

[PobodY]

"The winter mode, also recently named 'comfort' mode, starts out in 2nd forward and 2nd reverse."

Source: https://en.wikipedia.org/wiki/Mercedes-Benz_7G-Tronic_transmission