E220 CDi autobox problem

[dieselman]

Hi

A collegue as an E220 CDi auto. Intermittantly the car doesn't change above 3rd even on a light throttle. As soon as the accelerator is prodded the box will change up to 4th and 5th as normal with no increase in road speed.

Initially a new electronoic plate was fitted in the gearbox and then a new box was fitted. The fault still exists.

His own thoughts are that the throttle pot may be faulty as the box changes normally as soon as the accelerator is moved.

My thoughts lead to the gearbox control ECU, as I believe it was not changed with the gearbox.

There are no fault codes.

Any ideas would be welcomed as three local dealers were sure the new box would fix it.

 

[piestore]

auto box change

Hi dieselman

I would tend to agree with you that it is probably ETC unit as this is the only thing left ! My only other thought is that if the engine is performing even slightly below par it gives the gearbox very confusing messages as the required torque is not being produced.

This can be due to air flow meter or even choked injectors as niether of these will produce fault codes. does the car perform normally ???