I just checked the service manual and a solid light means the ecu key memory is blank and not programmed to the ignition key.
Has it had a new immobilisor ecu fitted do you know. If it has try this.
STORING NEW KEY CODES (VIRGIN MEMORY)
When the immobilizer ECU is first powered up, its memory is
virgin and the led stays on without flashing. To store the first
two key codes :
- run a key ON cycle with the first key: the led will switch
off for 0.5 sec and turn on again. When it turns on, turn
the key to OFF.
- turn the second key supplied to ON within 20 seconds.
The led will switch off and immediately flash 4 times.
Now turn the key to OFF. The two keys are now stored and
the immobilizer is activated (led flashes every 3 seconds as
a warning).
The two keys are now stored and the immobilizer is activated
whenever the key is turned to OFF (led flashes every 3 seconds
as a warning)
If power fails after the first key is stored, the system will reset
(first key data also cancelled). After the first key has been
stored, all vehicle and dashboard’s functions are enabled.
The key is not stored definitively if the second key is not
stored within 20 seconds.