The appearance of Volkswagen Group Ireland chief executive Lars Himmer before the Oireachtas Transport Committee was meant to address the concerns of – at the latest tally – 115,917 Irish motorists affected by its cheating software.

In the end it added little to our knowledge on the matter, save to let our public representatives vent some anger and frustration on behalf of a motoring public.

Attempts by committee members to delve into the technical detail of the cheating software – including Dessie Ellis TD who reminded everyone he was “a technician myself . . . so I would understand a lot on the electronics end” – didn’t get much further.

The hearing did reveal some confusion over whether the software cheated NCT inspections. Members were assured that unlike US tests, the NCT doesn’t measure for nitrgoen oxide (NOx) – the harmful emissions at the centre of the scandal. That arguably raises other issues about the priorities of our testing regime.

What we did learn is that VW has presented the first “technical solution” to its cheating software to German federal authorities. If this fix gets approval then they hope to start recalling cars and installing it from January. We also heard further assurances that any fix “shouldn’t impact on CO2 emissions” and therefore carry no motor tax implications.

“Shouldn’t” doesn’t exactly reassure in these circumstances. The automatic response to “shouldn’t” is “but what if?”

The reality is no one knows for certain, not even the boffins at Volkswagen. The problem is this is not a single fix. The cheat devices were fitted to three variants of diesel engine EA189. All three were fitted across at least 60 model variants, and combined with a variety of gearboxes. Authorities need to test the proposed fixes against all these variations. For some, a difference of 1g/km in CO2 emissions will move it into a different tax bracket.

VW executives have said the primary brief for engineers working on a fix is that it can’t hit fuel economy or CO2 emissions. What’s unclear is if the fix does push up CO2 emissions on some cars, will VW bin it and go back to the drawing board, leaving owners in limbo?

Mr Himmer may have made his apologies to the Oireachtas committee, but this scandal is still a long way from resolution.