One morning, some weeks ago, my car wouldn't start. It again failed to start that afternoon but started normally the next day.
I'm still wondering whether it was an immobiliser problem because the behaviour was similar to when a locksmith was testing a new key before it was programed.
However the fault code I retrieved was 44 - not the immobiliser code 54. How confident can I be that it was therefore not an immobiliser fault?

I also got code 71 but that was probably from a previous "TCL off" problem. This was the third time I'd seen code 71 & on each occasion I checked the flash count once or twice. However there is no code 71, as Madmagna has confirmed.

Has anyone retrieved a code that proved to be wrong - the fault was elsewhere?
Has anyone else seen an invalid code like my code 71?
Has anyone had a fault which should have generated a code but not retrieved it?

Has anyone retrieved a code that proved to be wrong - the fault was elsewhere? Yep... happens more often than you'd think
Has anyone else seen an invalid code like my code 71?Yep but mainly on sick ECU's
Has anyone had a fault which should have generated a code but not retrieved it? Yep.... also quite common

Code 71 is a TCL code:
http://i923.photobucket.com/albums/ad78/the_ash_1/71.jpg

Thanks for the info. However the details above are of code 71 generated by the TCL light; my code 71 was from the engine warning light. I've never retrieved a code from the TCL light.
Then again, each time the TCL-off light came on, the engine warning light came on a moment later. That might explain how the code came from the engine light - seems unlikely though.

its very likely especially seeing as you are using flash codes