i have since been to the garage had diagnostics error codes are po335rpm deleted,p1602 rev counter deleted,p1687 throttle body deleted,also told engine hunting due to defective motorised throttle valve now had new throttle body done rpm sensor done map sensor and crank sensor but still cutting out no differnce engine light comes on ,wont start,then starts but runs lumpy at idle can the engine ecu be at fault PLEASE HELP

I've had this problem for some time so I rigged an LED inside the car and connected it to various terminals on relay T9. When the engine cutout the relay had dropped out. The supply side of the relay was ok but the earth side was loosing a connection to earth (in the ECM). I am tempted to connect the earth side direct to earth but I cannot find out what functions I would be bypassing in the ECM. Does anyone know? I have checked all earths and even run a wire from the ECM direct to the battery earth. Strangely the engine always restarts after turning the ignition off and on again.

P1602/P1687 and other errors. What you need to do is to keep your focus on the connection to the ECU and to check the state of the generator. Follow this check list. 1: Check the 2 big male plugs on the ECU - are any of the small pins pushed into the ECU ? If so the ECU needs to be repaired. 2: Clean the 2 big female plugs with real contact cleaner - NOT wd40 - but real contact cleaner suited for electrical repair. Just blow it into the plug. Use a lot. Then shake the plug so remaining cleaner drops off. Then reconnect the 2 plugs. Check if the engine runs fine now. If not then repeat the procedure. I had to do it 5 times to get rid of multiple errors on my Stilo. 3: If the generator is old and used then replace it. Any power spikes and weakness will make the ECU mad (P1602). The generator should deliver some 14 volts when the car is running but it may fail intermittent. 4: Under the fuse box you will find 2 big plugs and relays. Clean them similar to described in 2. 5: Calibrate the throttle (P1687). Turn on the ignition for at least 1 minute - do not start the car and do not tuch anything. Then turn off the ignition. Wait one more minute. Then start the car. Wait at least one more minute and drive. Calibrate the throttle often and you may avoid problems of all kind with eg. cruise control and idle. The whole process - check and clean - should take some 30 minutes.

Two posts and already one thank !

Nice (sharing) people deserve nice rewards ...


Keep on that valuable habit, and BTW, welcome on board ;-)

Fault codes - and real fault codes - for Fiat Stilo - and other cars - can be found easily on automotive-manuals.net. I have often seen people are mixing things up eg. the believe a P1221 is a throttle body failure - but that is false - it is indeed an accelerator (speeder) fault. And some times a failure is caused by a bad connection. I recently investigated a P1221 fault and found it to be caused by a squezzed pin (B6) in the D4 connector that holds the signal from the track 1 of the speeder.