All Omega 2.2 16v Model Year 2003 4 door Saloons from VIN: W0L0VBF6931000001 and
all Omega 2.2 16V Model Year 2003 5 door Estates from VIN: W0L0VBF3531000001 are
Euro 4 compliant.
Applies to both auto and manual. So says the VCA database.
All these cars have Z22XE engines with later electronics and a pre-cat as opposed to the earlier Y22XE which is Euro 3.
The character "3" in position 10 of the VIN indicates that the car is MY 2003. Note that Model Years do not equate exactly to first registration years. So a MY 2002 car first registered in 2003 would not be Euro 4.
The best place to check your
vehicle registration is here using the TFL database.
Incidentally if you have a Z22XE Euro 4 Omega you can easily obtain a French Crit’Air 2 yellow vignette using just the V5c, if for example you want to drive in Paris.