Symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

Possible Causes

- Harness or connectors (CAN communication line is open or shorted) - Faulty Engine Control Module (ECM)

When Detected

When ECM is not transmitting or receiving CAN communication signal of OBD (emission related diagnosis) for 2 seconds or more.

Tech Notes

There is a service bulletin for the following Nissan models with U1000 code: 2002-2006 Nissan Maxima 2004-2006 Nissan Titan 2004-2006 Nissan Armada 2002-2006 Nissan Sentra 2005-2006 Nissan Frontier 2002-2006 Nissan Altima 2005-2006 Nissan Xterra 2005-2006 Nissan Pathfinder 2004-2006 Nissan Quest 2003-2006 Nissan 350Z 2003-2006 Nissan Murano Nissan Service Bulletin Code U1000 Service bulletin suggest cleaning engine and body harness ground connection to repair problem.

Description

CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only.