CAN Faults and Troubleshooting

The following outlines faults which may occur on the network. It is important to understand that the performance of the network and on-board diagnostic features, where a fault occurs, is entirely dependent upon the cause of the failure.

Thirty "hard" failures have the potential to cause system disruption and each failure has been assigned a number.

The following tables sort these failures into fault modes (1 to 9) where each mode is a level at which the network can detect a failure. There are two distinct categories;
1. Single identity source modes 2, 3, 4, 7, and 8.
2. Multiple identity modes 1, 5, 6 and 9.

Category 1, having singular faults can be readily located.

Category 2, modes have the same affect on the CAN but cannot be individually identified. Therefore a logical routine must be employed to eliminate each section of the line of communication, starting from the broadest aspect and narrowing down to the fault.

NOTE: All CAN faults are identifiable using PDU but may not be so with generic scan tools.

Three additional failures, 31, 32 and 33 are included and are referenced to external diagnostic checking via the J 1962 connector.