Fault code reader

[Leerav]

Hi I have a RAV4 d4d diesel 2003 I'm looking for a fault code reader can anyone recommend which one I should be using bought 2 OBD2 today they connect but will not link says failure.

[IanML]

I use a Windows laptop running Toyota Techstream with the special lead, eg Link.  Give full diagnostic facilities.

[Avalon]

I use Dash Commander with a generic ELM interface via bluetooth for quick and dirty fault code reading and basic data, a wired VCI lead with Techstream and a Windows laptop or a wireless VCI set-up on other occasions. Carista also works well on newer cars, but I haven’t tested it in an early (2003) car.

[Gerg]

I am responsible for a 2001 Corolla 1.4.  

A copy of Techstream (from eBay) does not work with that car (age?), although it works with a 2013 Auris perfectly.

The OBD2 protocol changed sometime after 2003 -2004 ('K - Line' to 'L - Line'?, I can't remember exactly) , but earlier on some cars, I think.

For what you are looking to do, I use one just like this and an Android phone (this model doesn't work with an iPhone):

https://www.amazon.co.uk/Bolongking-Diagnostic-Scanner-bluetooth-connection/dp/B07TV5K5Z9/ref=pd_rhf_ee_p_img_6?_encoding=UTF8&psc=1&refRID=8QK2FAJESDKRM95R1ZBG

But, be warned that there are so many copies of these, usually with different circuit boards inside, and that this one itself is using a cloned ELM 327 comms chip (the real ELM 327 chips cost more than this whole item) - all the cheaper ones do.  Mine is 4 years old, so I can't give a specific link to the exact one I have.  I think you are best guided by the reviews on Amazon for these items.

Mine works well with the 2001 Corolla, and all the other, newer cars I've tried it in for simple engine code reading.