Heard a master tech say 'ECMs are killing real troubleshooting', got me thinking...

I was at a shop in Dallas last week and this old timer was ranting that plugging in a scanner isn't the same as knowing how a pump times. But then again, these new engines are so integrated you kinda have to start with the computer. Which side do you lean on for a tough no-start?

3 comments

3 Comments

juliahall25d agoMost Upvoted

I read a post from a Bosch trainer who said the real skill is knowing what the scanner is telling you. Half the guys he sees can pull codes but can’t interpret a live data waveform. On that tough no-start, I’d start with the ECM just to check for crank signal and fuel pressure commands, then go manual from there.

the_olivia25d ago

Took me back to a job last week where the scanner showed a crank signal, but the damn thing still wouldn't fire. Spent an hour on live data before I realized the ECU was getting the signal but not using it. @juliahall, gotta watch those ghost signals.

nelson.cameron16d ago

Man, I feel that. Nothing worse than staring at a scanner reading that looks perfect but the engine just sits there. I had a Subaru last month - crank sensor waveform was textbook clean on the scope, but the ECU was ignoring it. Turns out the reluctor ring had a chunk missing. Scanner showed a signal cause the sensor worked fine. Just wasn't enough for the computer to sync. Live data will make you crazy sometimes.