Hi, had a 2nd hand 7 speed dsg gearbox and mechatronic unit installed into my car but for some reason it only drives in 2nd gear and reverse, with both the new and old mech units. with the old mech unit, connected to VCDS and it gives error code - 006300  - Function   Restriction due to Insufficient Pressure Build-Up - P189 C -

 

Does this indicate a problem with the mech unit, or does it mean that theres a problem with the new gearbox? 

 

Hi, I'm sure one of the techie minded people will be around to provide a better insight than I can, I can only relate to you my own experience when our Mechatronic unit failed.

 

Our unit failed because of a fluid leak from the internal pump within the mechatronic unit, eventually reducing the pressure required to operate the system properly all the way down to zero bar instead of the 40 bar required.

 

Fitting a second hand mechatronic unit can bring problems of its own judging by other owners experiences. A replacement mech comes from the factory partially coded to your vehicle using the chassis number, once installed the techie then has to install basic settings and any software updates, then a test drive before any final tweaks are added.

 

The internal pump produces the required pressure to enable the clutches to be depressed in much the same way as it would on a manual car, without the pressure it will not be able to function.

 

Your original mech may have had the internal pump fail which is why you are seeing the code you are. 

 

Sorry if this doesn't help.

Thank you, Going to try a different mechatronic and see if that helps. 

Have you programmed the new mech to the car with the VAG Software? Did you reset all the gears manually back to neutral before fitting the new mech?