I see so many posts from people who have a CEL light on and they don't have any means of reading the codes so I have a simple answer: get one now! If you think you have to buy something terribly expensive like the Nissan Consult system, you don't - there are cheap, effective solutions.
If you have a fairly recent smartphone (android or iOS) all you need to buy is a Bluetooth or Wi-Fi OBDII plug-in adapter - it's less than $20.00 and then download and install on your phone one of the dozens of scan tool apps out there. Many are free and others costs about $10. So for less than $20 you can skip taking your car to someone else just to find out the error code. Depending on the scan tool app you use, you can monitor, graph and even export reports of many key sensors and running components of your car and take a lot of the guesswork out of understanding the nature of problems you might be having.
