Grahambp1978

Hey guys.
Does anyone have a wiring diagram for 09 equinox 3.4 liter? Specifically, the 5 volt Ref A diagram would be awesome! Still trying to diagnose a p0641 code after changing all the engine sensors. Thanks!

Thanks!

Gumby22

The 5v 1 bus circuit provides reference to the EGR valve, MAP, cam, AC pressure, fuel tank pressure, and accelerator pedal position sensors.

If you’re not getting a reference signal at any of these sensors, the corresponding pins at the ECM are in connector 2 (has gray retainer visible when unplugged) at pins 33, 34, 36, 42, 43, and 44.

The back of the connector will have pin ID numbers on each corner - use those for reference to identify the correct ones.

hanky

If you replaced good sensors with another set of good sensors(we hope) , there is a good possibility a wire has managed to rub thru and is intermittently grounding the 5 volt reference voltage or possible a poor connection in the circuit allowing the voltage to drop out.

You are right , you will need a wiring diagram to see everything on the circuit and where you might need to check.
Sometimes we get lucky and find it pretty quick and other times it can take a lot longer,

repairman54

I use alldatadiy.com for the shop manuals for my fleet. There are no good free diagrams and the subscription at alldatadiy is not that expensive and worth it. Very detailed and intense but it has what you need for less than 15 min. of paid shop time.