2023 How to Check Codes Without Scanner Inquiry

[Mister421]

Hi - Does anyone know how to check OBD Codes without a scanner on a 2023 Yukon Denali? Check engine light came on however nothing including the GMC app is indicating anything wrong. I searched the forums but maybe didn't use the correct wording and also a general search across the internet but found nothing. I can check codes on all our other cars using just the dashboard or a bit of voodoo with the ignition switch. Is there a trick with these other than having a scanner?

Thank you in advance.
Brad "Mister421"

 

[KMeloney]

I don’t know the answer to your question, but can say that at least here in PA, Autozone (and maybe other similar places) will take their scanner out to your car and scan your codes for free.

So, if making an appointment at a shop and cost concerns are a part of your question, maybe this info is of some help.

 

[Joseph Garcia]

^^^^^x2^^^^^ Many auto parts stores will hook up their scanner to your truck for free, in the hopes that you will buy any replacement parts from them.

 

[WalleyeMikeIII]

Hit the OnStar button and request they run a remote diags to tell you why the Check Engine light is on.

 

[Mister421]

Hit the OnStar button and request they run a remote diags to tell you why the Check Engine light is on.

Thank you for the replies. I will give the OnStar button a shot. Truck is under warranty but I like to know what is going on before I take it anywhere.
Brad "Mister421"

 

[E_S_D]

Good luck with service. My 2023 Suburban had a check engine light as well as messages on the dash about brake system failure, service ESC, and service trailer brake system. Read the codes myself to get an idea of what was wrong and took it in for service. The service department was unable to run any tests because there were "no recent or current codes". They turned off the CEL and sent me on my way. CEL came on again two days later, this time with additional codes, took it back in, they were unable to run any tests because there were "no recent or current codes". Turned off the CEL and sent me on my way. CEL came on again the next day, took it in, they were unable to run any tests because there were "no recent or current codes", they turned off the CEL, however this time when I picked up my truck the CEL came back on immediately when I started it at the service department so they took it back and were able to run tests since there was now an active code in the system. Service tech told me they can only run tests on "active codes" with their testing equipment. He came up with a long list of possibilities and had to contact GM for assistance with diagnosis, I'm still waiting for the answer/repairs 4 days later. They are paying for a rental car while I wait ...

 

[Stbentoak]

Hit the OnStar button and request they run a remote diags to tell you why the Check Engine light is on.

If you don't have the proper OnStar package...IE; most expensive... They will not read codes for you. Been there, done that.....

 

[WalleyeMikeIII]

If you don't have the proper OnStar package...IE; most expensive... They will not read codes for you. Been there, done that.....

He said he had a 2023 Denali. He got the most expensive package included with his purchase for 3 years. He can get the diags.