Gearbox problems
QI have a 2011 Mito Sprint 135bhp with the TCT gearbox. Sometimes, when the weather is cold, even if I warm the engine up to normal operating temperature, the Transmission Failure Light comes on and the car will not engage any gear with the transmission mode light flashing. If I turn it off and try again sometimes it will drive in ‘D', but stays in
1st gear. The only way to get the car going is to connect it to ALF OBD and clear the codes: P294D, P290S and P2907. Despite searching on the interweb, I cannot find what these codes refer to.
When I first bought the car, a few months ago, I had a lot of issues – most of the electrical ones being cured by a new high-quality Stop-start AGM battery, plus replacement of the engine Multiair unit and for the MOT both rear calipers were replaced, so I have not stinted on looking after it.
The car has done 93,000 miles and I have a voltmeter connected which shows 14.2-14.3 volts when the engine is running.
When running normally, it works fine, except for the odd flat spot when kicking down. The transmission failure seems to coincide with overnight frost, which is why I warm it up before attempting to drive off under those conditions.
I have been quoted about £250 to check for software updates and re-calibrate gearbox clutches – none of the local Alfa specialists seem to have any experience with this TCT ’box.
Any help you can offer would be much appreciated.
Derek Mathers
AYou have hopefully eliminated the first problem which can cause numerous problems and that is the 12V battery. This was a good move and is one that if you had not already carried-out I would have recommended.
The TCT gearbox is a twin-clutch autoshift unit and uses electrically
managed hydraulic pressure to operate the gear selection and clutch operation. As you mention that the problem does appear to be when the unit is cold, this may be relevant, and it would be prudent to get the hydraulic transmission control fluid level and quality checked. The system does need de-pressurising using diagnostic equipment, and the system should also be cold when checked.
The transmission codes should be P09XX and so it may be a misinterpretation by your diagnostic system. If this is the case and we substitute the codes for P094D, P0905 and P0907. We get P094D which is Hydraulic pump system – over-temperature condition, P0905 which is transmission gate select position circuit - range/performance problem, and P0907 transmission gate select position circuit - signal high.
These codes would seem more in tune with the problems you have and may suggest that the electro-hydraulic system is at fault. This may be as simple as a poor connection problem or a faulty internal sensor or the problem may be more complex. I would first though ensure the multiplug connections are in good order.