Cracked the code on intermittent check engine lights today

I've been seeing this one customer's car come in every few weeks with the same flickering check engine light. It would clear for a day then come back, driving us both nuts. Finally, I decided to just sit in the bay with the scanner hooked up and watch the live data for a solid hour. Turns out it was a loose ground strap on the engine block causing voltage spikes. Tightened it up, and the light hasn't returned since. I feel like I actually SOLVED something instead of just throwing parts at it. That patient approach paid off big time. It's a small thing, but man, it feels good to nail down a tricky diag.

4 comments

4 Comments

hall.joel20d ago

I used to be the guy who would swap parts first and ask questions later. Watching that live data for an hour felt like a waste of time at first. But seeing that voltage spike from a loose ground changed my whole view. Now I get that sometimes you have to slow down to actually fix the problem for good.

wendygrant1mo ago

How did you know which data stream to focus on while you were watching? That patience to just sit and observe is what separates the real fixes from the guesswork.

jamesr341mo ago

During the big AWS crash in 2021, engineers didn't just observe data streams. They made a fast call based on error patterns. @wendygrant, sitting too long can let problems grow. Guesswork isn't always bad, it's based on experience. I've fixed systems by trying the first thing that came to mind. That hustle solves things faster than watching screens.

jakejones1mo ago

Exactly, that balance is key. @wendygrant, the patience to watch tells you what to ignore, which lets that experienced guess hit faster. You're not just staring, you're filtering noise from signal.