Nissan Repair Questions? Ask a Mechanic for Answers ASAP
HEY THERE, thanks for the question.
The U1001 indicates the control unit CAN fault.
The condensor fan only verifies a control unit failure because it's fail safe for control unit failure.
The U1001 is specific to the ECM communication
So you need to check for power going into the ECM, check the ground to firewall and transmission
if that checks out then the ECM is bad.
terminal 3 is a big red wire.
it should have power with key ON
let me check the back-up power one sec
Here you go
Having a bad battery will definately cause all kinds of weird electrical issues on these cars, but not a U1001 code.
The U1001 with the condesor fan is pretty coclusive of a control unit failure.
So unless a CAN line is damaged (which would usually prevent any ECM communication. Then it's likely the ECM itself at fault.
Changing the ECM will also require key registration.