Auto gear change delay

[speedygirl]

Hello everyone,
newbie here so please be gentle. My 2015 c200 1.6 diesel estate has developed a funny problem. A few days ago, in the really cold weather,start the car and drive off, the gears would be very slow to change up, revs would go to 3000rpm,and to encourage it to change i would use the paddle. Manual paddles shift would not come on,stayed showing D, . When i stopped and turned off and then on the engine again after a few hundred yards, it was perfect??? really smooth gear change,loads of power. This happens every morning for the past week and also EML has come on saying charge air intake sensor??
Another thing is that the little guide that shows how economically you drive,the green circle image,it doesnt show acceleration input? and Diesel consumption has increased too by about 1.5 litre per 100km. Anybody had similar issues. Also where would i find the charge air intake sensor,,,,is it just behind the mas airflow sensor?
Thanks for taking the time to read my first,albeit long ,post. carol.

 

[Blobcat]

What condition is the battery in?

Needs to be~12.4V with engine off at rest and ~14V when engine on and charging.
Modern vehicles have a much higher demand on their batteries and require a fully charged one to work. A lot of functions can be disabled or erratic with a partially discharged battery.

 

[speedygirl]

hmm, i will check. Funny, the stop start thingy is always amber, never comes on and i read that was to do with battery too. i will check the battery. thanks for the fast reply blobcat.

 

[Ron240]

When I start and immediately drive my car (2021 CLA 35) from stone cold in freezing temperatures the gearbox hangs onto the lower gears noticeably longer than usual before changing up, then all goes back to normal when the engine heats up.
I realise this is not the same as what you are experiencing, but I just recognised a similarity when reading your post so thought I would mention it.

 

[speedygirl]

when it first started happening it stayed that way for 12km, car was up to temp too,,,,,funny that it fixes itself when engine is reset. makes me think it is software related perhaps.

 

[speedygirl]

What condition is the battery in?

Needs to be~12.4V with engine off at rest and ~14V when engine on and charging.
Modern vehicles have a much higher demand on their batteries and require a fully charged one to work. A lot of functions can be disabled or erratic with a partially discharged battery.

battery at rest is 12.3v, goes to 14.6 when engine on. possible cause?? thanks

 

[Blobcat]

Well it’s charging ok, and 12.3 isn’t too bad. Check again first thing in the morning then look at getting codes read, see what is stored

 

[ajlsl600]

As above, but at really lo temps I suspect sensors get a headache a restart resets things and at that time Yr temps are prob up a bit. Cause prob sensors built by lowest bidder. Resistances diff at lower temps. Can bus reporting adversely effected. "modern electronics"
Today pistons go up down more efficiently but a trillion more possible failures are introduced by human ingenuity. Ain't life grand..

 

[speedygirl]

As above, but at really lo temps I suspect sensors get a headache a restart resets things and at that time Yr temps are prob up a bit. Cause prob sensors built by lowest bidder. Resistances diff at lower temps. Can bus reporting adversely effected. "modern electronics"
Today pistons go up down more efficiently but a trillion more possible failures are introduced by human ingenuity. Ain't life grand..

the sensor is genuine mercedes. but not made by the quality of old.

 

[speedygirl]

Well it’s charging ok, and 12.3 isn’t too bad. Check again first thing in the morning then look at getting codes read, see what is stored

The only fault stored was charge air intak3 P007B

 

[ajlsl600]

Did that clear and not rtn?

 

[mioba]

Not uncommon for merca to hold gear longer in the cold weather - its the cars clever computers doing this to make the gbox oil warm up faster, preventing wear. Noticeable more on earlier 722.6 boxes.

 

[EmilysDad]

Not uncommon for merca to hold gear longer in the cold weather - .....

Not just the preserve of a Merc ..... my auto Vauxhalls did the same.

 

[mioba]

I only had autos on mercs, I did have a volvo with a CVT - but that disnt really count.

 

[EmilysDad]

I only had autos on mercs, i dis have a volvo with a CVT - but that disnt really count.I

The only CVT I've ever driven was a Fiesta years back ..... a very strange experience ...

 

[mioba]

Worst box ever it was - needed rebuilding twice in my 8 years the it spewed the oil everywhere. Pity as the car itself was fantastic. I had about 6 volvos before i went Merc

 

[Ron240]

The first and only CVT transmission I have ever experienced was in a 1976 Honda Civic, which was manufactured 8 years before I passed my driving test.

 

[onefortheroad]

Hello everyone,
newbie here so please be gentle. My 2015 c200 1.6 diesel estate has developed a funny problem. A few days ago, in the really cold weather,start the car and drive off, the gears would be very slow to change up, revs would go to 3000rpm,and to encourage it to change i would use the paddle. Manual paddles shift would not come on,stayed showing D, . When i stopped and turned off and then on the engine again after a few hundred yards, it was perfect??? really smooth gear change,loads of power. This happens every morning for the past week and also EML has come on saying charge air intake sensor??
Another thing is that the little guide that shows how economically you drive,the green circle image,it doesnt show acceleration input? and Diesel consumption has increased too by about 1.5 litre per 100km. Anybody had similar issues. Also where would i find the charge air intake sensor,,,,is it just behind the mas airflow sensor?
Thanks for taking the time to read my first,albeit long ,post. carol.

It sounds very much like it's going into limp mode ,hence the 3000 revs and reset after switching off, after 5 or 6 same faults the eml should light and give a clue with some code or other.

 

[speedygirl]

It sounds very much like it's going into limp mode ,hence the 3000 revs and reset after switching off, after 5 or 6 same faults the eml should light and give a clue with some code or other.

The fault code came up after a few days of this happening. P007B,cleared and came back after a day of driving. very odd.

 

[speedygirl]

Did that clear and not rtn?

it cleared and returned a day later.??