2023 Yukon Denali CEL flashing

[dverstra]

As stated, problem started with a CEL flashing. Then had 3 messages on the center driver display "Service ESC, Rear Axle System Off, Service Traction Control". CEL code was a P0308. Misfire on cylinder 8.
I setup an appointment for Monday morning. What am I in for?

 

[jfoj]

Flashing CEL is usuauly a misfire indication which tracks with your P0308. So the question is are the other Service Messages typical when a misfire occurs, I do not know.

But what I would do is get your battery and charging system tested. Often when the batteries start to fail on vehicle in the last 10-15 years that have so many computers employed on the vehicle, they often have problems communicating with each other and really strange things start to occur. Not unusual for certain modules to actualy shut down and go "off line" when battery/charging Voltage issues occur in order to conserve power to allow the engine to continure to run.

The other thing is there have been fuel pump control modules that soft fail and will cause driveability and misfire issues as well.

If you have a Voltmeter, start with the basics, if you can get to a parts store and back, have the battery and charging system tested.

BTW, what is the build date on the vehicle?
How many miles on the vehicle?
Have you had any prior battery or starting related issues?

Good luck.

 

[ReaperHWK]

Also if it’s flashing don’t drive it. That means a pretty big misfire and you can damage your motor. It’s flashing for a reason…..

 

[jfoj]

I also keep forgetting about the stupid AFM and bent pushrods or even worse.

Hope your problem is simple.

Good luck.

 

[dverstra]

Flashing CEL is usuauly a misfire indication which tracks with your P0308. So the question is are the other Service Messages typical when a misfire occurs, I do not know.

But what I would do is get your battery and charging system tested. Often when the batteries start to fail on vehicle in the last 10-15 years that have so many computers employed on the vehicle, they often have problems communicating with each other and really strange things start to occur. Not unusual for certain modules to actualy shut down and go "off line" when battery/charging Voltage issues occur in order to conserve power to allow the engine to continure to run.

The other thing is there have been fuel pump control modules that soft fail and will cause driveability and misfire issues as well.

If you have a Voltmeter, start with the basics, if you can get to a parts store and back, have the battery and charging system tested.

BTW, what is the build date on the vehicle?
How many miles on the vehicle?
Have you had any prior battery or starting related issues?

Good luck.

Thanks for the replies

Not sure where to find Build Date
23,600 miles on vehicle
No previous problems with the battery or starting

 

[jfoj]

Open the drivers door and look at the lower right door jam for the VIN sticker and it should have the month and year on the tag, I think in the lower right of the tag??

I suspect every battery that is more than 3 years old, but even younger batteries can have issues and only testing can determine their health.

Does the engine still run rough and misfire after turned off and restarted?

 

[Doubeleive]

your under warranty so worst case scenario is you are without your ride for a while, cost is 00.00

 

[Antonm]

Flashing check engine light means there is a catalyst damaging event occurring. You may, or may not, be damaging the engine, but the light means you're damaging the catalytic converter.
...

 

[dverstra]

At the service appointment, they diagnosed a faulty injector on cylinder 8. They replaced that and the other issues went away. All was covered by the warranty. I asked for the warranty info on the Denali. In addition to the warranty info, on the same sheet, it mentions replacing an other injector on "Bank 2" in October of 2023. So I have 6 more to go?? Hope not.