This is one 2013 thread from an owner abroad. It lists what to check, but it ends with the owner about to try the diagnostic tool, so we don't know the cause. For an earlier case with the same symptom (code P1612, loss of immobiliser serial data), see Fuel pump replacement and Reading fault codes.
The symptom
A 2.2 had not run for eight months. It started, and if the pedal was pressed it revved, but about a second or two later it cut out, as if the fuel had been cut. The engine light came on with the key and stayed on. A new battery made no difference, and neither did the spare key. The alarm remotes also wouldn't disarm the alarm, although both had always worked before.
What owners suggested
- Try the spare key. The first thing to rule out, but it didn't help here.
- The key code. One owner said that when his key code was wrong, the car started, ran for a few seconds and the engine light came on. That points to the immobiliser. Reading it needs a diagnostic tool (an OP-COM, with the car's security code).
- The loom of doom plugs. The blue and black plugs behind the coolant tank, which carry the immobiliser line (the white/yellow wire in the black plug) as well as the throttle pedal, fuel pump relay and other signals. See Throttle failure and limp mode: the connectors to check.
- The fuel cut-off switch. One owner asked whether it had been checked. Another said that because the car did start and run briefly, there had been fuel pressure, which a tripped cut-off switch would prevent.
- The alarm. Pulling the alarm fuse stops the alarm going off. One owner said the original alarm works independently of the ECU, so it shouldn't stop the car starting, and that dying after two seconds sounds like the immobiliser cutting out. They said to read the fault code with a universal reader.
- After ECU programming. One owner said that after you reprogram the ECU (for example after replacing it), switch the ignition off for 10 seconds before you try to start.
If the alarm won't disarm
A car that has sat for months can have flat fob batteries or a drained main battery, which can look like a locked immobiliser. Check the fob batteries and the car battery first. See Central locking and alarm.