Computers/Control - CAN Code, Diagnostic Tips/Guidelines
Date: May 7, 2010
CAN COMMUNICATION CODES - DIAGNOSTIC TIPS & GUIDELINES
APPLIED VEHICLES: All 2005 - 2010 Nissan vehicles
Related to communication codes U1000, U1001, U1002, U1010:
Always diagnose the communication codes first.
When a module reports a U1000 code, it is typically operating normally; however, there is a communication error external to that module on the CAN network.
U1000 indicates an error. V-CAN diagram or CAN Diag Support Monitor provides data to determine the location of the error.
Complete the CAN diagnosis with CONSULT-III (C-III).
Open ASIST first and then open C-III using the Consult Utilities icon. This step will help identify the CAN type on many vehicles using the SIS function.
Ensure the correct CAN type is selected. Selecting the incorrect CAN type will lead to mis-diagnosis.
View the V-CAN screen or print all CAN Diag Support Monitors (shown below).
The V-CAN diagram screen is a snap shot only. It must be refreshed after any changes.
Read the V-CAN diagram using the key provided OR reference the appropriate Electronic Service Manual (ESM) to analyze the CAN Diag Support Monitor data. Determine the incident according to the display.
If V-CAN diagnosis is not available or inconclusive, refer to the basic CAN diagnostic guidelines shown below. These represent electrical values of the CAN system measured at the Data Link Connector or connectors at non-termination units.
To properly perform these basic checks:
The battery should be disconnected for resistance checks.
Improper module configuration or incorrect part numbers may set CAN DTCs.
Low battery voltage may set CAN DTCs.
Always confirm the power, ground, and CAN resistance at a suspect module before replacing the module. Resistance should be close to 60 ohms at the module (measured with the battery disconnected). The resistance at terminating modules should be close to 120 ohms. Examples of terminating modules include IPDM, ECM, or BCM. Reference the appropriate ESM to determine the terminating modules.
DEFINITION OF CAN CODES
V-CAN Diagram Screen/CAN Diag Support Monitor - Step 3 Illustration
Battery is Possibly Connected - disconnected and recheck resistence