Intermittent starting issue 2011 Yukon XL Denali

[Dadnali68]

one other thing to consider in the mix is the ignition cylinder, that is where a tech2 would be handy, one giveaway is the no lights on dash, if the ignition switch is not working no lights on dash...... just food for thought

I should rephrase. No lights as in no check engine lights. The dash lights up and everything works and looks as it should until key turns from run to start. Even remote start will put on the exterior lights, I can hear the fuel pump cycle, then no crank.... sometimes... more often then not so far it will start and run.

 

[Doubeleive]

I should rephrase. No lights as in no check engine lights. The dash lights up and everything works and looks as it should until key turns from run to start. Even remote start will put on the exterior lights, I can hear the fuel pump cycle, then no crank.... sometimes... more often then not so far it will start and run.

99% of the time a cel is smog equipment related and would not prevent the vehicle from starting or running (with the key).
very rare cases there could be something, but not much
what a cel "may" do is prevent a "auto start", or prevent "cruise" from working, that's sort a fail safe because it doesn't know if you are aware of whatever issue may be happening, or if the cel light is burnt out, etc
for instance if it was overheating..... and it caused a error on the dic such as low power, pull over and shut off engine then it would not auto start
or if there was a low oil level warning, cat inefficiency, etc things like that.... it just defaults to no auto start.
there could still a ignition issue though until it is ruled out, a tech2 would tell you what (it see's) as the key position in the case of no start.
for instance of you are turning it to start and the tech2 shows it is not changing (only showing run position) then you know

 

[Dadnali68]

99% of the time a cel is smog equipment related and would not prevent the vehicle from starting or running (with the key).
very rare cases there could be something, but not much
what a cel "may" do is prevent a "auto start", or prevent "cruise" from working, that's sort a fail safe because it doesn't know if you are aware of whatever issue may be happening, or if the cel light is burnt out, etc
for instance if it was overheating..... and it caused a error on the dic such as low power, pull over and shut off engine then it would not auto start
or if there was a low oil level warning, cat inefficiency, etc things like that.... it just defaults to no auto start.
there could still a ignition issue though until it is ruled out, a tech2 would tell you what (it see's) as the key position in the case of no start.
for instance of you are turning it to start and the tech2 shows it is not changing (only showing run position) then you know

Know of a good place to pick up a clone or a used real tech2? Might not be the worst idea to pick one up, I have an 08 cobalt as well it would work with.

 

[Doubeleive]

Know of a good place to pick up a clone or a used real tech2? Might not be the worst idea to pick one up, I have an 08 cobalt as well it would work with.

well.......they have gone up in price they used to be $300, now they are $400 and a pinch. some online places that sell them are SUPER sketchy
there was a reliable site called chinacardiag but they went under and now there are copycats that I would say are likely unsafe
I would say this one is a relatively safe buy, not too many places will cover you but ebay does if it does not arrive or is defective

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[mikez71]

Starter relay? I know you said fuse box was replaced... not sure if that comes populated with new fuses/relays?