2015 Yukon electric/running problems

[Hunter c]

I have my in-laws 2015 Denali Yukon xl with the 6.2l. About two weeks ago my mother in-law was driving and all of sudden traction control abs and cruise control lights came on. Then the ac stopped working and would be intermittent. and starting running really rough she says then shuts off I had it towed to my house hooked the scanner up and found misfiring on cyd.3 (p0303) and a mutilple misfire on all cyd. ( p0300) I went ahead and done full tune up on it cleared the codes and still did the same thing with all lights back on also telling me to roll down each window and back up at a time. But when truck sits for about 3 days it will start up and run perfectly fine with no issues for about 1.5 mins then everything comes back on to running off shutting off and not wanting to start back up. I’m down to a faulty ecm or wiring or injectors. If anyone could please help out with suggestions or if that have had same issues I’d appreciate it thanks.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally assist you with your issue, but other members of this Forum much more knowledgeable than me in this area will chime in.

What type of scanner do you have?

 

[RoadTrip]

I have my in-laws 2015 Denali Yukon xl with the 6.2l. About two weeks ago my mother in-law was driving and all of sudden traction control abs and cruise control lights came on. Then the ac stopped working and would be intermittent. and starting running really rough she says then shuts off I had it towed to my house hooked the scanner up and found misfiring on cyd.3 (p0303) and a mutilple misfire on all cyd. ( p0300) I went ahead and done full tune up on it cleared the codes and still did the same thing with all lights back on also telling me to roll down each window and back up at a time. But when truck sits for about 3 days it will start up and run perfectly fine with no issues for about 1.5 mins then everything comes back on to running off shutting off and not wanting to start back up. I’m down to a faulty ecm or wiring or injectors. If anyone could please help out with suggestions or if that have had same issues I’d appreciate it thanks.

A couple known weak points you could check for are internally corroding negative battery cable (replace the cable and clean the grounding points), and the other is check for corrosion underneath the underhood fuse box (replace the box).