2010 Traverse 3.6 - Misfire codes & flashing MIL

ProAuto wrote:

I wonder if I can read data from 2 scan tools at the same time via an obd tee. Hmmmm.

I've always been curious if I could tee in two scanners. :lol: Never got around to trying it. If you do, please let us know how it turned out.

If that tool can do it, then that means the ecm is capable of pushing misfire and other pids simultaneously.

Correct. My understanding is that, it isn't an issue of the ECM supplying the desired combination of PIDs, but the scan tool *asking* for the desired combination.

I think I've discovered something today. As I said before, voltage on this car is rough... Even with the alternator disconnected. This crank signal looked rough to me, so I checked for ac voltage on the 5v ref. Think this ac voltage might be the problem?

Any luck with this one?

Not yet. I think my problem is too much ac voltage on my crank 5v ref. We've been really busy so I haven't been messing with it. I'm thinking about putting a bridge rectifier on the reference wires to the crank sensor. Unless I can figure out where this stray voltage is coming from.

This vehicle is fixed. Replaced the ecm and all is good. Something inside this module was creating excessive and hashy looking AC voltage throughout the car. With the new (used) module installed my 5v references look cleaner on the scope and my crank signal looks slightly sharper, but not noticeable unless the before and after are compared side by side. Thanks to all who took the time to respond.

Thank you for the follow up!