Scanmyopel app on an Android phone.
Works on OBD2 cars (although I never tried it on a desmond).
Cheap as chips. Leave the dongle in the glove box & you can clear the cat codes as soon as they pop up.
I was able to access the engine, gearbox and ABS/traction ECUs on my 2,6 & 3.2 V6
Could be a viable option
Trouble with ScanMyOpel - I've not used it for ages - was it claimed to do everything, but in reality couldn't do many Omega systems. I've not got an Omega to try any more, but if coverage has improved and anyone has the required bluetooth interface, gotta be worth a punt (from memory, they do a freebie/trial)
2.2 petrol is very strictly EOBD, and inconsistent with OBDII, so generic OBDII scanners are not really recommended for it. Not quite sure how that will pan out with ScanMyOpel, as its not a generic OBDII software, but uses the generic OBDII hardware. We need a 2.2 owner to try
. Though it could be, for example, the genuine interface works and the cheap chinky clones we all own doesn't.