Damn my technical curiosity.

A few days ago I got the new Nexus 7 tablet which means, armed with an Android device, I could now hook up an OBDII Bluetooth dongle and get all kinds of interesting numbers from my DB9 beamed live to my tablet's screen. So I got the Torque app loaded up and plugged in the dongle to the engine port (right hand side port in the drivers foot well) - to my surprise it seemed to work immediately with idle revs, throttle position being measured accurately . Brilliant.

Until, that is, 5 mins later when I got a dash message saying "Engine System Service Urgent" and a red dash light . I immediately switched off and turned off the ignition. Stupidly after seeing everything was normal after turning it back on I continued my journey. When I got to the next junction, the dash lit up like a christmas tree, briefly said "DSC system failure" and another few messages flicked past then the engine stalled . This time, I saw sense and immediately pulled the OBDII dongle. Being at a junction, had to get on my way again- Thankfully the car started first time and other than an "Emissions System Service Due" (or something similar) drove the next 30 mins without issues (now the dongle had been removed).

It goes without saying that the dongle has gone straight in the bin and now I'm trying to establish if any damage has been done. I feel a bit of a plonker for messing about like this but have done it a few times before and my friend's R8 has had the same dongle fitted and works flawlessly.

I now have "Emissions System Service Due" message up whenever I start the car . Still, not long before the car heads for a service where I hope it can be cleared...what else should I prepare myself for?

I would add - don't worry too much, if you were soldering stuff into the engine bay - worry, otherwise not. To say the sensors and the like on AM's are sensitive is like saying Michael Gould is not a big fan of poor people get a code reader, read the codes, google them, sigh in relief and continue enjoying your lovely car

It sounds as though the dongle is polling rather than simply monitoring signals, causing bus congestion. Possibly this is caused by unrelated Bluetooth signals putting the dongle in polling mode. Turning Bluetooth off on your phone may obviate the problem but the simplest thing is, as the other replies suggest, to remove the dongle when you're driving.

Not all ODB2 Bluetooth/Wi-Fi dongles are created equal. After doing a fair amount of research and trying several different models in my V8V and G55, I've settled on the pricey ODBLink MX Scan Tool:
http://www.scantool.net/scan-tools/pc-based/obdlin...

I've used it in both vehicles and it works well. The only drawback is that it doesn't support iOS devices (iPhone/iPad) due to limitation in Apple's Bluetooth accessory support. If iOS support is important, then you need a Wi-Fi dongle like those made by PLX Devices.

I've seen some Bluetooth ODB2 dongles for 1/10th the price, but you get what you pay for.