Anyone know of a way of interogating the Bosch 2.7 ECU to get diagnostic fault codes out ? Will one of these OBD CAN modules and software interface to it ? have a feeling one of the water temperature sensors have failed: engine tick over is only increased by 500rpm at cold startup - thought it was 1000rpm? odd very minor stumble when at < 2000 rpms in gear when driving (rare, but there).
I am having a similar problem with my 456GT. It acts as though the ECU thinks the engine is hot when it is cold - very hard to start, poor idle and drivealbility when cold. Also, the cooling fan goies on when cold. I measured the room temperature resistance of both ECT sensors and they were about 2.6K Ohms, which is where they should be at ~20 C (measured between pins 45 and 30 of the harness connector). I am starting to think it is an ECU issue - maybe the pull-up for the ECT sensor. The diagnostic codes can be read out by pushing the button that is located inside the kick panel that covers the ECU(s). Turn the key to the run position but don't start the car. Then, hold the button down for about 10 seconds and the Check Engine Light will blink the codes. Good luck in finding a chart of what the codes mean, I have not yet found one. As for a CAN interface, I am not sure if the Motronic 2.7 supports this. There is a proprietary interface to a Ferrari test system called the SD1. I don't know if this is a CAN interface or what the protocol would be. I hope this helps!
I believe without an SD-1 (or -2 or -3) you are out of luck. OBD-II is, IMO, a big advantage of the 456M (and I believe the 97 456GTs).
My cooling fans come on after about 5-10 mins. It doesn't seem to affect the car in any way, and it starts and idles OK (albeit a little lumpy once off the choke). I have only had the car about 7 months, and I assumed that the V12 just generated more heat than other cars - it blows warm air quicker than my other 2 cars (BMW Deisel & Merc).
