OBD use in the MOT

there aint (at least on mots)only permitted obd use im aware of is a connecter released by snap on for sun dga temp+idle measurement which is now apparently on the dvsa approved list,i guess youre figuring to measure emissions via obd when you cant rev or get a reading.unlucky.......

A few years ago it was originally proposed that, certainly Euro 6 and possibly Euro 5 emission testing would not involve any measuring equipment of any kind and would rely only on the vehicle software regulating the emissions and the "emission test" would involve using the OBD port and some form of approved diagnostic reader.

The VW/Audi scandal put an end to that idea overnight.

I've just bought a new Bosch gas/smoke tester (I had to for the new regulations which was a bit of a pain!) and it comes with the OBD pickup for rpm and engine temperature. I also had this as an "extra" on my old Bosch setup.
If I were you (and I DO know it's more money!) I would get the OBD interface. It's well worth it!

Define "dismantling"! I know exactly what you're getting at but usually it's just a case of opening a hatch, no tools required, so I can't see it as a problem. And, most times, you don't even need to do that.
Oh, and don't forget it's not just a cable. It's Bluetoothed to the main unit which I suppose makes the cost look more reasonable.

We don't have any means of checking the revs on our old antiques, but if the engine won't rev, or the reading is zero it comes up with a prompt to check that the probe hasn't fallen out. At that point I press to abort and it gives me a printout with all the info required by DVSA and with a zero reading on it. You can guess we won't be spending £500 on doing it different. I'm surprised I can get the needed results on these old clunkers but your modern stuff needs OBD access. Damn I hate to admit they might be doing something helpful.

Since the update was installed I have aborted more Diesel tests in a week than I ever did before in a month .
The lower emission levels just can't be detected without RPM pickup to trigger the machine to record a result.
I've been going around in circles trying to get the records that show all the information in its measured form, but the resultant efforts are causing me grief, a lot of test results are being created that show on paper that the test as aborted due to no result detected, but they also show that RPM and Oil temp have been bypassed. ( The oil temp would have been tested on the first aborted attempt )

The software is also poor quality and not well designed, The manufacturers blame the DVSA for the short period between them being told the parameters and the implementation dates.

I don't see the DVSA as being helpful in this, I would not be surprised if it would marked down negatively if I keep having days or weeks like this.

Guidance would be welcome in a widely published form for the trade regards to OBD and its permitted use, if restrictions to its use on only euro 5 onward diesels only for example, and facia panel removal where this may be necessary .
Just to stay on the right side of things.

no reading on our dga means no print,no proof of temp/idle etc,just wondered if the obd pick up registered ANY rpm change to obtain a print.petrol rpm on smart charge and the odd diesel temp are a perennial pain in the arse

I have few if any idle measurements now,i do my best when a petrols failed the bet test to get an rpm reading but its an evens bet itll read stupid and to get off that screen on a dga once youve selected rpm yes means going back to the beginning and starting all over again,our ve visit a few weeks back assured me that its pretty common now and not to worry.oil temp by and large measures ok.

my machine technotest 498. prompt's me to connect rpm leads .if i cant get a reading .from exhaust .bit of a pi$$ take after spending £834 .on updates .but i get the diesel print out i need .