Why does nobody talk about how scan tools made us forget how to actually diagnose
I was at a shop in Dayton last month helping a buddy chase a misfire on a 2004 Silverado and the first thing his new guy did was plug in the scanner and start swapping coils. Back when I started in 1998 we didn't have any of that, you listened to the engine, pulled a plug, checked for spark with a screwdriver against the block, and actually thought about fuel and air before you touched a part. The kid had the scan tool out for 40 minutes reading live data and still couldn't tell me why cylinder 3 was dead. I grabbed a vacuum gauge and had it figured out in 10 minutes, intake gasket was leaking on that bank. I mean the tools are great, don't get me wrong, but it feels like the scanner became the answer instead of a starting point. Anyone else notice the newer techs freeze up when the code reader doesn't hand them the fix?
Had a similar thing happen with my nephew's Honda Civic last winter. He swore it was the transmission because some forum said so, spent two weeks reading codes and watching YouTube. Turned out a $12 coolant temp sensor was making it shift weird. The car ran fine after that but he never did trust the scanner again.
Man, that story hits home. I watched a guy spend two days chasing a rough idle on a Ford Ranger and he threw a throttle body and two sensors at it before he even checked for a vacuum leak. Turns out it was a cracked hose behind the intake, five dollar part, ten minutes of work. The scanner showed him fuel trims were off but he didn't know what that even meant, so he just started guessing. Codes tell you where to look, not what's broke, and half these kids never learned the second part.