05 Yukon EVAP Parts Cannon.

[burdbrain68]

I have shot the parts cannon at my 05 Yukon 5.3 L59 Flex Fuel.
Tank pressure sensor pigtail missing 5V reference.
Tech II scanner indicates "Failure Detected Within The Advanced EVAP System"
Aside from tracing from the ECM pins perhaps someone has encountered this condition.
Are there chaffing points inherent somewhere on the harness. I have looked for the obvious.
This RWD makes easy sighting where 4X4s may have issues.
From Doug Burd SLC Utah

 

[Fless]

Welcome from not far from Aurora, CO (you know, the Venezuelan gang hangout)!

I suggest pulling both ECM connectors and looking for water migration (especially at the lower part of the connections) and pin fitment. If there is water migration -- or even if there isn't -- clean the contacts and maybe replace the connector gaskets. At that point you can test the pressure sensor wire and the output from the ECM.

 

[Miami-Dade]

@burdbrain68 Moved you here from 2021+section.
Welcome from NYC!

 

[strutaeng]

Yeah, need to figure out why the 5V reference is not there.

I "think" you could temporarily jump another 5V reference to test the circuit, but I would just try to figure out the problem instead.

If you have to, chase back to where the 5V reference comes from. Check the wire from there to the pigtail connector for continuity and resistance. I'm not aware of pinch points for that branch of wiring. Isn't the one that runs from the ECU/fuseblock down inside the frame rail?