Nissan Maxima Service and Repair Manual: DTC U1000 CAN communication
DTC DETECTION LOGIC
Symptom: Displays "CAN COMM CIRC [U1000]" as a self-diagnosis result of combination meter.
1.CHECK CAN COMMUNICATION
Select "SELF-DIAG RESULTS" mode for "METER/M&A" with CONSULT.
>> Go to "LAN system". Refer to LAN-9, "Condition of Error Detection".