O2 Sensor Question (Code 91)

[1FatPony]

I pulled code 91 and I am trying to figure out the problem. I just installed a new engine and had everything disassembled. I just folowed the wires that came out of the O2 sensors and found an orange wire went to this little box that is suppose to be mounted to the left side of the engine compartment (passanger side) except mine wasnt connected. Is this the ground for the O2 sensors and could that be the problem why i pulled code 91?

I would go down and see if grounding that box would solve it but my battery died.

If this isnt where it is ground where could I find the ground wire?

 

[jrichker]

The orange wire is the O2 sensor ground. Any clean & shiny spot on the engine will be a good place to ground it. It will cause problems if it isn't grounded.