a4 b5 1.9 tdi avant

[logic5]

Last couple of days noticed it won't start straight away thought my fault too quick. But now it seems to got worse will turn over but not fire will do so eventually after a few times read code it say (17978 engine start blocked by immobiliser) any help
Its the 99 facelift model eng code AVG

Thanks

[Doctle Odd]

I wouldn't worry about that code. IS the coolant temperature sensor genuine. IS there any air getting into the fuel system?

[logic5]

never changed temp sensor not drawing air did notice when starting imm light on dash flickers when not starting and clicking heard back of dash .Was toldcheck 109 relay but had a look can't see one so any help please
Thanks

[Doctle Odd]

If the immobiliser light is flashing bring your key to a locksmith, he will check if the signal is weak. What did you scan with?

[logic5]

scanned with autel vag scan tool will try locksmith thanks