I had this error and the Engine Management Light come up on my 2.2 JTS 159 Saloon this week just 90 miles after I completed a full service. It relates to a positioning diagnosis of the camshaft on the exhaust.
Instantly I'm thinking...... 'crap, here comes a new cam chain and balancer invoice'.
However the issue seems to be solved - thanks to friendly advice from Autolusso on the phone (I think it was Ned).
Cause: Essentially when I flushed the engine and topped it up the suggestion was that some crud may have interfered with the solenoid / sensors - the alternative is that I actually need a new cam chain. The fix? Give them a damn good clean. My Engine Management Light is now gone and the car seems to accelerate faster. Winning
This is an easy fix and requires the following tools and no mechanical experience
Tools: Socket Set, Long Nose Pliers
Step 1 Disconnect the battery.
Step 2 Remove the Engine cover (the red bit with Alfa Romeo across it) using 8mm socket. The bolts will not come all the way off the engine cover fully loosed them and then using the black end of the engine cover gently lift until it pops off the two fixings on the nearside.
Step 3 With the Engine cover removed undo the bolts that fix the coil pack to the rocker cover at the top of the engine. Once the bolts are fully removed gently lift the coil pack until it pops free of the spark plugs. There is no need to unplug the coil pack from the wiring loom.
Step 4 On the driver side of the rocker cover and in the same recess as the 4s park plug holes you will see two cylinders with wires connecting to sockets at the top of them these are the solenoids. Gently disconnect the wires and then unclip the loom from it's two fixings on the front of the rocker over so it is out of your way. Unbolt both the solenoids, and remove the bolts completely.
WARNING: The solenoids are not just the plastic bit on the top of the metal cylinder so do not try to separate the two.
Using your long nose pliers gently and with even pressure lift the solenoids from their seats free of the engine and place into a clean container with petrol in it.
Step 5 Clean the solenoids by letting the petrol break down any of the thick dark oil deposits that may have built up (mine had been in there fore 112000 miles. Once the deposits have cleaned through blow through hole at the end the loosed any particles that are sat in the three mesh collars on each solenoid. Re submerge in clean petrol.
Step 6 Inspect the sockets that you removed the solenoids from. It will be worth carefully cleaning any deposits from this area I used cotton wool buds with petrol on them. You do not want to take dirt back into the engine when you replace the solenoids, and you do not want to leave cleaning materials in the sockets.
Step 7 Replace the solenoids (Grey at the Bottom, Black at the top) and reassemble the other parts. Finally re-connect the battery.
Step 8 Start the car and hopefully the EML light will have disappeared. If not and still the same code consider replacing sensors and / or new cam chain.