Has anyone had this part go bad? It’s the box on the passenger side by the firewall with the big wires going to it. My electrician says it’s bad & my Yukon only runs on gas mode, never shuts the engine off. I’ve been looking for a used one but haven’t found any, new is too expensive. Any help?

 

Sounds like bullsh!t to me.

Codes?

 

incorrect if it was bad it would not start and you would get Service Hybrid System chances are if it's not going into auto stop the battery is too hot or the load draw is too high i.e A/C on front and back, throttle input is too high, over 30mph..