What are those plug in things that the garage charges you 40€ to plug in to your computer to find out what the fault is.

And more so  where do I buy one?

Want one for my 2009 T5.

And can you use it to reset certain things; I want to turn off the rain sensor, for example.

Easy, go on eBay and buy a basic one. Search for plug in code reader and state model.

“What are those plug in things”

They are called OBD2 code readers.  The basic ones are all pretty much the same so just get the cheapest one that has good ratings from eBay/Amazon should be available for £15-£20.  I’d recommend spending a bit more and getting a bluetooth/wifi one that you can use with your phone these are available for ~£30.  You can get apps like Torque that will allow you to see a bit more data than the basic readers will show you.

“And can you use it to reset certain things; I want to turn off the rain sensor, for example.”

You may need a slightly more advanced one specific to your car or one that connects to a computer with the correct software for this.  The basic ones will be able to reset the generic fault codes on your car but any manufacturer specific codes may not be cleared by a generic code reader and certainly functions like enabling and disabling features on the car is highly unlikely to be possible on a generic reader.

You may be better off finding the fuse or relay for the rain sensor and removing that. Assuming the manual controls will still work fine with this removed?

“OBD” is what you need to be searching for.

My tame petrolhead recommends Autel for a generic “keep in glovebox” reader.  The one he recommended to me at the time was the MaxiScan MS309, though they have a dozen different models at wildly different price points and “the time” was two years ago.

VCDS if you want to play with settings.

ive got a few generic readers and they are great for quick and dirty fault codes but the minute i want to start modifying the ECU i reach for the dealer level tools – in my case ive done it with Lexia and peugeot planet to activate things like Cruise control / speed limiter and disable auto headlights etc.

I also find that the propriatory stuff gives more accurate fault diagnosis – so if the generic reader throws up a wide range code or something expensive i stick the dealer stuff on – for example i had a dodgy horn – unknown to me till mot. The garage i used just pumped the fuse box under the bonnet full of fuses and the car threw all sorts of codes at me via the generic reader

stuck on lexia and it told me to check engine bay fuse board based on the codes where i saw that there were much more fuses than there should be and it was shorting out the canbus signals.

also do not be tempted to leave those bluetooth things in your OBD port as ive seen the aftermath of a few that have caught fire.

* not that my flirtations with torque were very successful , i found it very limited – gave alot of info , gave alot of graphics , looked very slick  – most of it useless filler junk.

A basic one will allow you read codes and possibly reset some of them.

If you want to turn off / change things then you’ll probably need something a little better than a boggo reader.

If you don’t know what you’re doing though…….

fair point bigyinn Nothing quite like bricking your car ECU

I bought a £4 to £5 blue kkl cable off eBay and downloaded the free version of vcds lite from the rosstech website. Gives enough info to read and reset warning lights. If you want to activate cruise control etc you’ll need the full paid version of vcds.

The generic obd readers will only display fault codes shared across all vehicle manufacturers. Not really worth buying.

* not that my flirtations with torque were very successful , i found it very limited – gave alot of info , gave alot of graphics , looked very slick – most of it useless filler junk.

Did you use the paid or free version? I’ve always found the paid version good – particularly if you purchase the vehicle specific add one.
Be wary of the cheap Bluetooth versions – they tend to have unchangeable passwords which are 1234. Evil bastards who pull up next to you in traffic can have a great deal of fun with you!

Really? Given the limited function of the cheap readers I’d be surprised if anything could be done especially if it was already paired.

It’s always worth looking for car- specifics too. Like, f super and formiddable for Ford are awesome, and barely any more expensive than a cheapy. Accessport for subaru is miles more expensive but lets you reflash the entire ECU if you want- map, advance, you name it. Depends what you want.

If you just want codes any cheap code reader will work, but its just generic OBD codes. I have a £20/£30 quid ebay one, it can do basic monitoring as well, eg TPS, MAF etc, handy for pulling a code without getting out the lap top.

If you want to change coding on a T5 I would use VAG COM VCDS, genuine from ross tech, or an illegal ebay clone for about £50, just dont update it.

VCDS is also much better for diagnostics, logging, output tests etc. Loads of support and info online as well as on Ross Tech.

OBDeleven is meant to be a VCDS equivalent, but I have no hands on experience of it. They do sell coding apps if you dont want to manually change coding.

Garage is more likeley to use Snap On Solus, Modus, Autel Pro range etc, but they are £££.