This $5 device should be sitting in your glovebox, next to your tire pressure gauge, pile of Bojangles receipts, and box of emergency fuses.
You are miles from anywhere, the check engine light comes on, did your ride just experience catastrophic engine failure, or is your gas cap sensor acting up?
All vehicles after 1996 are required to support the ODBII standard, previously reading this port was the job of certified mechanics with expensive scan tools spitting out obscure codes, and over time became something that required a trip to the auto parts store.
No longer. Today you can read engine data, see fault codes with the plain English explanation of what they might mean, and clear trouble codes to see if they come back or after you fix the cause. You can purchase a Bluetooth scanner on eBay for less than $10 with free shipping, (Check the reviews first and make sure people had success!) and use a free app in the Android App store.
Just last month my check engine light came on. I pulled over and plugged in to check the cause, my engine temp was through the roof. Back in the day I would have been able to tell this simply by looking at that handy temperature gauge on every car, but long ago many of those became “Dummy Switches” reading only three states of cool, within bounds, and overheated, but apparently not sensitive enough to let me know when my coolant was boiling.
A quick google search of my issue and my car revealed it may be due to a design defect, and I should I park my car on an incline, squeeze my coolant hoses and “burp” my car.
Yes, Burp it...
Sure enough, a short Swedish massage later my coolant tank belched and bubbled and the entire system returned to it's regularly scheduled programming of cooling my car, I cleared the code and was back on my way, monitoring my trip via my android phone reassured everything was operating within normal temps.
Idle issues, O2 issues, meaningless fault codes triggered by finicky gas caps sensors and tire pressure gauges, put one of these in every glove box you have. At less than the cost of gas to AutoZone and back, it’s one device almost guaranteed to pay for itself, I made a point buy three, one for each glove box so I’m never caught without, and I would strongly suggest everyone else does the same.