Eh Eye Ate Dub Yah ✡︎ 
I hate #shady #car #repair shops..
A friend was told she needed to spend $800+ to fix her check engine light.
I have an OBD-II reader connected to a laptop via USB, so I plugged in and pulled the #codes - the knock sensor and both O2 sensors tripped AT THE SAME TIME!
This usually indicates bad fuel, not bad O2 or knock sensors, so I reset the code to test if it was an ongoing issue. It does not seem to be ongoing; the Check Engine light didn't come back on, and no new codes popped. Fixed in 15 minutes for $0.
If it codes up again, which is a possibility ('08 Saturn Aura) I'll look deeper into the issue, but if both the O2 and Knock sensors were bad, the ECU would've thrown codes back out immediately, or after I revved the engine a few times.
She made it home (about a 15 minute drive) without a code popping back up, so I'm confident it was just bad/wet gasoline.
Bibliothèque Diderot de Lyon
Norpan
Adeline
Verfassungklage@troet.cafe
Dirk Messner