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Jake
Jake, Nissan Technician
Category: Nissan
Satisfied Customers: 3906
Experience:  Experienced collision repair technician, Pulaski Tech graduate and DSM hobbyist.
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2005 nissan maxima 3.5 v6. codes P1212 and that CAN

Customer Question

2005 nissan maxima 3.5 v6. codes P1212 and that CAN communication fault code U1001, vehicle cranks but does not start, also the odometer does not work, can't see the PRNDL on cluster and the Aux fan is on max high when key ignition is on also the headlights are on. Sometimes it will start and run but the transmission is in failsafe.
Submitted: 1 year ago.
Category: Nissan
Expert:  Jake replied 1 year ago.

HEY THERE, thanks for the question.

Expert:  Jake replied 1 year ago.

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.

Customer: replied 1 year ago.
I know all that whats your best opinion to look for. I checked the grounds and i found a broken ground on the battery negative lead. I fixed that but still no go.
Expert:  Jake replied 1 year ago.

The U1001 is specific to the ECM communication

Expert:  Jake replied 1 year ago.

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.

Customer: replied 1 year ago.
What pins should i check at the ECM?
Expert:  Jake replied 1 year ago.

terminal 3 is a big red wire.

it should have power with key ON

let me check the back-up power one sec

Expert:  Jake replied 1 year ago.

Here you go

Customer: replied 1 year ago.
119 and 120 have power with key on backup power is available with key off
Customer: replied 1 year ago.
but why would the car start randomly and also sometimes every time if my battery is completely dead and i have a jump box on it to start it would that have any issues
Expert:  Jake replied 1 year ago.

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.

Expert:  Jake replied 1 year ago.

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.