wyeselespeed

Hi Smaky I couldn't believe it either (I cut the wrong wire at first as my Italian isn't great but then some say my English isn't much better!), I can only assume that the Xenon is prevented from doing it's height setting cycle if he lights are switched on when the car is moving, I can't think of any other reason for the connection. It will be reconnected with something I can disconnect easily, as it might happen again due to the headlamp design. Is it worth drilling the Xenon controller and fitting a drain rather than the rather hopeless attempts to stop the water getting in . Failing that, I am considering extending the loom to the Xenon controllers and mounting them upside down. Cheers

Hi, Fixed it at last OK so how about this, it was all caused by....... the left hand Xenon control unit, yes it was full of water and burnt out. Face lift Selespeeds run an vehicle speed wire to the N/S Xenon (N/S only!). Its not a CANBUS connection, its the green/red wire to the headlamp unit, I have cut the wire while I await a new Xenon control unit. Selespeed now works fine. So if nothing else sorts the P0720 fault on a facelift/Xenon 156 try disconnecting the Left hand headlamp connector. Thanks to everybody who replied to my post. I'm sure I'll be back for more assistance. Ed

Hi Smaky, Thanks for the reply, I have replacements so I'll give it a try. however I noticed that the Selespeed parameters display is showing very odd gearbox and clutch temp readings,which I think are derived from the engine temp ECU sensor, so I'll put a new one of those in first then try the ECU. Lots of conflicting web based info on P0720, some suggests that output speed sensor and gearbox/clutch temp sensor outputs are in series .........?? I'll let you know if I get anywhere, I'm struggling to find wiring diagrams for this particular 57 plate model (I guess it's the re import Australian version). Cheers

Oh.............., so I might as well give up now. I have tried different Selespeed ECU, Body module, Speedo and hard wired 20 Pin plug above gearbox, ripped up carpets to check for the mouse damage, disconnected and cleaned every connector I could find. I just keep getting P0720 error. It's pretty sole destroying so very sorry hear your woe's. I reckon this could be my last Alfa which is a shame because when it works its great. Thanks for the update. If anybody (Smaky??) has any bright ideas please let me know. (Will a 20V turbo FIAT manual box fit? as a last resort). Cheers great to know I'm not alone ( or maybe not.... ).

Oh deep joy, I thought I might just have a chance of fixing it, can't bring my self to scrap another Italian car! Did you change the ABS/ESP unit , that's next on my list, if you tried that I might give it a miss. Just as a matter of interest did the problem start after an alternator change (clutching at straws here). Thanks for your reply. Cheers

Hi, Did you both manage to resolve this problem I'm chasing the P0720 error on my 07 registered 156 selespeed. I can't seem to get to the bottom of it. The fault sometimes goes away after driving for 15 to 20 minutes (not fun but I needed the car). It always comes back on startup in the morning (cold start). The car has a new Batt and Alternator. all speeds are seen at the ECU live data. Tried another Selespeed ECU, same problem. After a error reset the light comes on again after 100 yards or so (could be distance or speed that triggers it, I'm not sure). Car has been jump started, in it's past life! Cheers