2004 Yukon XL (Non Flex) cranks but doesn't start.

[2004YukonXL_SLT]

Put the old crank sensor back in. The more variables you introduce, the more complicated the diag becomes.

Will it fire up on ether?

Back to the basics: verify spark, fuel, air (and compression, if you get to that point).

Yeah it fires up on either sensor. The reason I swapped it out was because my code reader that I currently have threw a crankshaft position sensor code.

 

[2004YukonXL_SLT]

Good point @Fless At this point, I don't think we have been able to determine if the crank position sensor was bad to begin with... I almost mentioned going back to the original sensor for now, at least until it can be determined the sensor is junk. For some reason, I didn't.

Note for the OP: A good bi-directional scan tool will allow you to dive in to see what the sensor is doing. For less than $300, a Tech 2 will do that for you PLUS the ability to do things like crank position sensor re-learn, a million different module diagnostics and various other sensor reset/test/programming functions. Like I said earlier... If you plan on keeping this truck (or a GM of similar vintage), having a Tech 2 can save huge amounts of diagnostic time and money doing things DIY instead of paying a shop. It will be way more advanced than your immediate needs, but for the money, you will be ready for the more advanced functions you might need later on.

Sounds good, it sounds like something that could be good for when I try to get my S10 running with the LS in it. Especially when both trucks are being driven and inevitably have issues.

 

[2004YukonXL_SLT]

Yeah it fires up on either sensor. The reason I swapped it out was because my code reader that I currently have threw a crankshaft position sensor code.

Just want to make sure I worded that correctly. It HAD a crankshaft position sensor code.

 

[S33k3r]

Check the ground from the passenger side of the engine to chassis. Had this same crap happen to our Suburban 2500. I had a friend from another enthusiast group suggest this. It fixed a problem that had the Suburban down for the better part of a month. On the flip side, we are now chasing down another electrical fault that prevents the door locks and windows from working, and there is no power to the cluster. When things warm up a bit, some cluster components start to work. And the OBDII port has no power <sigh>. Going to take it to my mechanic, but we've been sick and contagious so it's had to wait a bit.

 

[ExEl03X4]

We had a clogged secondary catalytic converter that caused similar symptoms. We never did figure out why it broke down inside.

 

[houstontaylor]

The mass air flow sensor is also a possibility.