2021 GMC Denali 1500, Service ESC, Service Parking Brake, Steering Assist Reduced and Flashing Engine Light

[Anthony Simler]

Here I am leaving my home one day when all these warnings pop up. I was about to pull over when they all of a sudden disappear one at a time. 2-days later, different story. All the lights come back on and the truck is running rough and the lights won't go off.

My truck has less than 26K miles and this is totally unacceptable. I plugged my diagnostics tool into the OBD port and two codes show up...twice. P0304; Cyl. 4 Misfire Detected and P050D; Cold Start Ignition Timing Performance. What the heck??

Taking it to the dealer tomorrow to see if they can figure it out. Numerous posts on this same issue and I'm hoping for an answer as I get ready to travel next month.

[Bikerjon]

21 hours ago, Anthony Simler said:

Here I am leaving my home one day when all these warnings pop up. I was about to pull over when they all of a sudden disappear one at a time. 2-days later, different story. All the lights come back on and the truck is running rough and the lights won't go off.

My truck has less than 26K miles and this is totally unacceptable. I plugged my diagnostics tool into the OBD port and two codes show up...twice. P0304; Cyl. 4 Misfire Detected and P050D; Cold Start Ignition Timing Performance. What the heck??

Taking it to the dealer tomorrow to see if they can figure it out. Numerous posts on this same issue and I'm hoping for an answer as I get ready to travel next month.

Welcome to the forum. Very sorry to hear about this. Let us know what the dealer diagnosis is.