HANDRAIL AS 2340577 - Caterpillar

Table 1
Diagnostic Trouble Codes for the CAN Data Link
J1939 Code Description Notes
639-9 J1939 Network #1 : Abnormal Update Rate The ECM detects that another controller has incorrectly stopped transmitting a J1939 speed request (TSC1) or another controller has incorrectly started transmitting a J1939 speed request.
The warning lamp will come on.
639-14 J1939 Network #1 : Special Instruction Another controller has incorrectly stopped transmitting a signal on the CAN 1 data link.
The warning lamp will come on.
The engine limp home strategy will be enabled.
1231-9 J1939 Network #2 : Abnormal Update Rate The ECM has detected that the CAN 2 data link is not functioning.
The warning lamp will come on. The following background information is related to this procedure:The CAN data link is also known as J1939 data link. The data link is an industry standard for sending data between different devices in the same application.High-speed data is transferred via the data link. The data link cannot be accurately tested without complicated equipment. The data link requires a resistance of 60 Ohms between the two wires to transmit the data correctly. This resistance is made up of two 120 Ohm resistors. The two resistors are known as "Terminating Resistors". The terminating resistors should be at opposite ends of a data link circuit. If this resistance is not present, then the data will be intermittent or unreadable.Note: The wiring for the J1939 data link is a shielded twisted-pair cable. If the wiring is damaged, the replacement type must be shielded twisted-pair cable.
Illustration 1 g03717599
Schematic diagram of the CAN 1 datalink
Not all connectors are shown. Refer to the Electrical Schematic for the application.
Illustration 2 g03717152
Schematic diagram of the CAN 2 datalink
Not all connectors are shown. Refer to the Electrical Schematic for the application.
Illustration 3 g03717619
Typical view of the pin locations on the P1 connector
(23) CAN 2 +
(45) CAN 2 -
(46) CAN 1 +
(47) CAN 1 -
Table 2
Troubleshooting Test Steps Values Results
1. Inspect Electrical Connectors and Wiring
A. Turn the keyswitch to the OFF position.
B. Inspect the connectors in the circuit for the CAN data link.
Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
C. Perform a 30 N (6.7 lb) pull test on each of the wires that are associated with the CAN data link.
D. Check all the wiring associated with the CAN data link for abrasions and pinch points.
Damaged wire or connector Result: A damaged wire or damaged connector was found.
Repair: Repair the damaged wire or the damaged connector.
Use the electronic service tool to clear all logged diagnostic codes. Verify that the repair eliminates the fault.
Result: A damaged wire or damaged connector was not found.
Proceed to Test Step 2.
2. Check the Data Link