Late Gear Shift Up, Gear Change up at high Revs - Intermittent fault - S212 E350 Estate 2011

[Seftonbarn]

Bit of a strange one this that has been going on for several months. It has been plugged in and there are no relevant fault codes. Occasionally, when starting the engine it kinda struggles to start and coughs a little before firing up. When the car starts like this, when I drive off it doesn't change up gear until it reaches about 2500-3000 revs. So when I am driving around town at 20-30mph it is sitting at about 2500 revs in, I guess, 2nd or 3rd gear. It won't change up until closer to 3000revs. On another day, when I start the car and it starts normally with no hesitation, when I drive off the gear change up is smooth and normal. In both cases the engines itself sounds and feels as if it is performing normally. Any ideas from you clever people would be very much appreciated.

 

[markjay]

Has it been plugged to MB STAR? Or to a generic OBDII scanner?

 

[Seftonbarn]

Has it been plugged to MB STAR? Or to a generic OBDII scanner?

It was plugged in to a newly purchased Snap On device from my local garage.

 

[easyonthegas]

Would it be worth resetting the gearbox system?
Process - 1. Switch ignition on, 2 - press accelerator pedal to floor for 10 seconds, 3 - switch ignition off, 4 - release accelerator pedal, 5 - wait 2 minutes before starting engine, 6 - car will need to re-learn your driving style

 

[DSM10000]

Would it be worth resetting the gearbox system?
Process - 1. Switch ignition on, 2 - press accelerator pedal to floor for 10 seconds, 3 - switch ignition off, 4 - release accelerator pedal, 5 - wait 2 minutes before starting engine, 6 - car will need to re-learn your driving style

That will do little to nothing.

It needs to be plugged in to a Star system. It may be that the gearbox behaviour is due to an engine issue.

 

[Flash]

Had exactly same issue on same engine.

I pin pointed it down to a split engine breather pressure control valve.