The $300 scan tool that lied to me for a month

Last month I had a 2015 Silverado with a mystery misfire. Codes said cylinder 5, so I swapped the coil, plug, and injector. Still missing, so I replaced the fuel rail too, that was $300 in parts. Turned out the wiring harness had a chafed wire hidden under the intake. My cheap scan tool never showed the live data drop, so I chased the code instead of the signal. Anyone else trust a generic scanner too much and burn cash on parts you didn't need?

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miamitchell18d ago

I used to think my scanner was the best money I ever spent, but now I get it. I had a similar thing happen on my buddy's F-150, chasing a crank sensor code for weeks. Replaced the sensor twice, cleaned every ground, even bought a new PCM connector, all because the scanner said so. Finally broke out a wiring diagram and found the real issue was a broken wire pinched in the firewall, no code for that. These cheap tools are fine for basic stuff, but they only tell you what the computer thinks is wrong, not what's actually happening. The real skill is learning to watch live data and think about the whole circuit, not just the part it points at. That $300 mistake taught me more than any YouTube video ever did.