A tricky matter – replacing a clutch on a Smart fortwo

In this repair case we would like to show you that even the seemingly simple replacement of a clutch on a Smart fortwo 451, 1.0 MHD, 2007-2014 can ultimately prove to be a tricky matter.
After the technician's repair, the engine still did not start and three dashes were shown on the vehicle display.
What happened?
After replacing the clutch, the technician wanted to program in the new component using the diagnostic unit, but this did not lead to the desired result.
At the same time, the error "P1800 Adaptation faulty" was read from the error memory. In spite of a further check of the work carried out and a second attempt to carry out a gearbox adjustment, no positive result was achieved.
After consultation with the diagnostics hotline, the following explanation provided help.

The solution

From a mileage of approx. 100,000 km this phenomenon can occur more frequently. A broken shaft of the electric motor inside the clutch actuator is the reason why, in this case, neither the new clutch nor the transmission could be programmed in.
If the driver ignores sporadic shifting difficulties in the automatic transmission for a longer period of time, experience has shown that these shaft breaks occur more frequently. The adjustment module is no longer actuated sufficiently with a defective shaft, which leads to a faulty feedback signal to the gear control unit. A prerequisite for a successful engine start is therefore no longer given.

Our repair tip

When repairing the clutch, you should simultaneously check the clutch actuator including the electric motor and – if necessary – replace it. Afterwards you can make the necessary basic settings with the diagnostic unit.

On the basis of this information, the technician then checked the components mentioned. The defective components were replaced and the repair was successfully completed.