This car has had a second hand engine and gearbox fitted by another garage but developed a gearbox fault on road test. It started developing gear selection issues and then ended up with no gears and the 3 dashes in the gear display. It has been extensively played with now and basically now will not start and I can not get it to carry out a gearbox selector adaption.

Using Mercedes Star Tester we can retieve the following fault codes.

35 - Turning angle sensor adaption.
36 - Incremental sensor adaption.

I have tried repeatedly to carry out an adaption but it just reports adaption failed and then seems to run the gear selector motor through its full up and down range for a couple of minutes and then stop.

I've checked the turning angle sensor on the side of the gearbox and can see that it is running through its working range (voltage increasing and decreasing) when the selector motor is operating as described above.

The selector motor has two hall effect sensors (the incremental sensors) in it, both of which are working correctly.

If I disconnect either the selector motor or the turning angle sensor, the ECU logs the appropriate fault codes, so I assume that when everything is plugged in, the ECU is happy with the signals from these sensors. I just don't know why it won't carry out an adaption.

I'm beginning to think I have some sort of software glitch as a result of it being played with on various different diagnostic machines. Can anyone shed any more light on this? There is much head scratching going on here!