Problems with Upshifting 722.9 7G-Tronic Plus

[User]

Has anyone had similar problems? I have a GLK 350 CDI 4MATIC and the problem is that when I accelerate more aggressively the gearbox downshifts as it should, but then the gear stays in 4th and does not upshift even if I release the pedal a little. The RPM is high, the speed exceeds 120 km/h, and 4th gear remains in the same position. But when I accelerate evenly, the gearbox shifts perfectly up to 7th gear. No error codes are displayed. I replaced the CPV valve and cleaned the air flow meters with a spray cleaner, and before that, I replaced the turbocharger and transmission fluid. Now I took my car to the local MB dealer for service and they tried to find out the reason. They told me that there are cr@cks inside the DPF because soot accumulates at the outlet of the filter, on the surface of the DPF and at the end of the exhaust pipe.

Could this "faulty" DPF cause gear shifting problems when gas flow is high?

 

[Mersovod]

May cause power limitation, but will also trigger DPF errors. See VGS data.

 

[User]

Here are some pictures of the DPF outlet.

 

[star10]

The DPF looks good but it looks like the transmission valve body or ETC unit is faulty.

 

[User]

Is it strange that there are no fault codes? Local MB dealers either don't know how to do anything or don't have the necessary knowledge to do anything without existing fault codes.
The only thing they recommend is to simply replace the first part, and if that doesn't help, then the second... and so on.
In that case it will cost a fortune.
I recently installed XENTRY PassThru but I'm not very familiar with it yet.

 

[Rade1978]

Have you tried adapting gears with XENTRY? It might help. Use XENTRY to adapt torque and gear shifting.

 

[User]

I think the local MB dealer did a transmission adaptation before I replaced the PCV valve and cleaned the MAF sensors. But at that time it didn't help/solve the problem. I think after replacing the PCV and cleaning the MAF sensors the gear shifting is much better than before but only under steady acceleration and if I accelerate quickly the transmission stays in 4th gear.

After the last service at the local MB dealer they did a forced regeneration but didn't notify me about it, but I checked with XENTRY that this happened. The fuel filter was also replaced according to the maintenance schedule. At home I read the service report and it said (these pictures were also taken from the DPF) that the car was running rough and the exhaust was blowing. Later, I checked the boost tube connection. The green O-ring there was broken. They sent a new one and I replaced it myself.

I checked/tested the differential pressure sensor and I think it is OK. I haven't driven this car for a while because I was looking for the best deal from the manufacturer on the DPF pipe. I need to do more testing before purchasing a new DPF.

 

[Rade1978]

Understand... Is the DPF sensor manufacturer Bosch?

 

[Mersovod]

The condition of the DPF can be assessed using the differential pressure sensor readings. Normal pressure is 4-6 hPa at idle and 0 hPa with the ignition on.
Connect the diagnostics, take the vehicle for a test drive and perform a short test before turning off the ignition. Then you may see the fault codes.

 

[Rade1978]

Also check all pipes (hoses), especially from the intercooler.