Possible causes – Controller Area Network (CAN) communication harness is open or shorted– Faulty Engine Control Module (ECM)– Poor harness ground connection. Tech description Usually the problem is poor harness ground connection. There is a service bulletin for the following Nissan models with U1000 code: 2002-2006 Nissan Maxima2004-2006 Nissan Titan2004-2006 Nissan Armada2002-2006 Nissan Sentra2005-2006 Nissan…