09 M13A auto - Intermittent no start condition P1621

[FJ43]

Hey guys!

I have a 09 with a M13A and auto transmission.

There is a intermittent fault with the vehicle not starting occasionally. When this happens, a fault code logged is P1621

I have tried another ecu/iimmobiliser/key set from a running vehicle with exact same numbers but the problem still persists.

Has anyone faced a similar issue or had the same code logged.

Would be very grateful if someone could shed some light as to where i should look.

Thanks.

[zook123]

Swapping over the parts mentioned won't work anyway as they would need to be paired. Have you tried the spare key?