Automatic E250 CDI, no 7th gear, engine warning light... dreading the cost of repair

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New Member
Aug 15, 2021
West London
E250 AMG Sport CDI 7G-Tronic
Today I was heading down the motorway in my 63 plate E250 CDI 7G-Tronic
The journey from home to the motorway (about 10 min) was completely uneventful, the car performing normally.
Joined the motorway and got up to 70 and was cruising in 7th gear as you'd expect. We got to the 50mph average speed check zone at the M25 end of the M4, so I dropped down to 50 and popped it into cruise control.
All was fine for the entire 50 zone, and when I saw the national speed limit sign, I used the cruise control stalk to bring the car back up to 70.
This was where things started to go wrong. As the car brought itself up to 70 and settled there, the engine revs sounded a bit high so I checked the dash and the gearbox was still in 6th gear... normally it goes into 7th at that speed.

So I disengaged cruise control and manually held the car at 70, and then a bit faster to see if it would change up... nope.
So I clicked the steering wheel gear+ button (can hardly call it a paddle to be honest lol) and even at 80 it just wouldn't go into 7th.

Then I noticed the engine warning light and my heart just sank. I've had this since July last year and it's been nothing but reliable for me until today.

I probably should have just pulled over and called a recovery service to get me home, but we were on our way to the Wales v Italy match in Cardiff and there was no way we could have been recovered home in time to get into our other car (56 plate Honda Civic 2.2 CTDI). So instead we stopped on the hard shoulder, and turned the car off completely. Left it for a few minutes, then back on... thinking it might have been some kind of computerised glitch as the fault appeared when using cruise control. Unfortunately the engine light came back on, and didn't go off, and the gearbox was still playing up. I decided to turn back at the next junction and drive 35 minutes back home.

The whole way back, I was having to manually click the gear+ button on the steering wheel to upshift as the 7G-Tronic box was having none of it. It would downshift on its own, but not upshift. I later found that it actually WOULD upshift, but only at ridiculously high revs.

Apart from the thing not shifting automatically, the engine seemed relatively OK, if not just a little underpowered... but that might have been psychological, as I was trying to be really careful with it to usher it home without causing too much damage.

I was wondering if anyone here might have an idea what might be causing this, or similar experience with their 7G-Tronic, and what might need to be repaired, not for the purposes of me trying to fix it myself - I fully intend on taking this round to my trusted MB specialist - but so I can start to come to terms with how much this might end up costing me to get sorted.

thanks in advance 👍
The engine light was amber by the way, not red. Hopefully it means I've not done any damage by continuing to drive it, but I will be getting it checked out.
I'll update this thread as I go along, cheers
Don’t panic Mr Mainwaring! First thing to do is get the fault codes read, otherwise it’s just guesswork. Wouldn’t have thought it’s caused any damage as like you say it’s just the EML not a red ‘stop driving’ message. It does sound similar to a DPF pressure sensor kind of symptom, which is a pretty common one, and fortunately they’re only about fifty quid and about a ten minute job to swap out.
I know you said you are going to take it to a MB specialist (sensible) but it can be worth getting a decent OBD reader such as an icarsoft MB or a Carly which won’t break the bank (sub £150) so you can read codes and reset the EML yourself, plus other useful features. They’ll never be as good as MB’s own Star diagnostic tool, but still surprisingly good for the price.
In the meantime, have check for anything obvious like fluid leaks, and probably best keeping driving it to a minimum just to play it safe.
Hope you get it sorted quickly without too much expense. 🤞
Thanks for the encouragement Chugg. That iCarsoft MB looks wicked to be fair, might get one regardless... I like gadgets haha.
First of all though, I will be taking it round to my local MB guys, they've been awesome with me since I started using them and I genuinely trust them not to do any work that's not needed.
No probs mate 👍
That’s good to have a trusted garage, especially as it a MB specialist.
Yes the iCarsoft is very handy and can be kept in that car for just the kind of situation you were in. I have the iCarsoft and was worth the investment, good for all sensors and airbags etc., and says which one is the problem so you’re not just changing parts for fun. It has a basic OBD reader for all makes too which worked fine on my mates Audi Q7 to diagnose a swirl flap fault (although I think swirl flap faults are standard in those! 😂). Might work on your Honda too as a bonus. I haven’t used the Carly, but that looks pretty nifty too. Have a search on here for some threads on them. KillerHERTZ has done some good reviews.
It might not be a gearbox problem (as suggested). If the engine is down on torque the gearbox may have to hold on to gears. Could be as simple as an airleak. Codes will give a clue though as it could have many potential causes.
It might not be a gearbox problem (as suggested). If the engine is down on torque the gearbox may have to hold on to gears. Could be as simple as an airleak. Codes will give a clue though as it could have many potential causes.
I has similar problems with my E280 shortly after I bought it.
A scan indicated "lack of boost pressure".
The cause was turbo failure.
Fortunately the turbo was replaced under warranty.
That cured the problem.
I had to go away for work, leaving the car at home undiagnosed for a while. I got back and immediately took it to my garage.
Diagnostics indicated there was an air leak in the turbo system, needed some new intercooler piping.
£450 all in, that included MOT which was due next month so I just asked them to do it all at the same time.

Thankfully gearbox was fine.

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