ARM AS-UI ROCKER 20R3322 - Caterpillar

Use this procedure to troubleshoot the data link if a problem is suspected with the data link. Or, use this procedure if one of following diagnostic codes is active or easily repeated.
Table 1
Diagnostic Codes
J1939 Code and Description Conditions which Generate this Code System Response
639-9
J1939 Network #1 : Abnormal Update Rate Communication issue on the Global data link between the generator and the ISM. One module is no longer broadcasting. The code is logged.
1231-9
J1939 Network #2 : Abnormal Update Rate Communication issue with the fuel valve and the ISM on the CAN data link. The code is logged.
1231-14
J1939 Network #2 : Special Instruction All communications on the data link have been lost. All communications on the data link have been lost.
2241-9
Source Address 241 : Abnormal Update Rate The engine ECM is not communicating with the ISM. All communications on the data link have been lost.
2452-9
Generator Total Real Power : Abnormal Update Rate Communication issue on the Global data link between the ECM and the EMCP. One module is no longer broadcasting. The code is logged.
Gas substitution shuts off. Note: If the only active code is 2452-9, troubleshoot the customer supplied load feedback signal. Refer to Application & Installation Guide, LEBW0026 for additional information.Use this procedure to troubleshoot the electrical system if a problem is suspected with the CAN data link or the Cat Data Link.Note: This procedure checks for an open or for a short in the data link circuits.If Caterpillar Electronic Technician (ET) will not communicate with the ECM, refer to Troubleshooting, "Electronic Service Tool Does Not Communicate" before you begin this procedure. The procedure will verify that electrical power is being supplied to the ECM and to the service tool connector.The data links are used to communicate information between the engine ECM and other control modules that are a part of the application. Cat ET also communicates with the ECM via the data links.The service tool connector contains connections for electrical power and for the data links.When the keyswitch is in the OFF position, Cat ET may communicate with the ECM. However, the communications may be disrupted and the communications may require frequent reconnection. To avoid this problem, place the keyswitch in the ON position when Cat ET is being used.Cat ET may display the following error message:"The version of the ECM is not recognized and the integrity of the changed parameters and displayed data is not guaranteed."This message indicates one of the following conditions:
The flash file in the ECM is newer than the version of Cat ET.
The latest version of Cat ET has not been installed.
Illustration 1 g03383096
Illustration 2 g01444702
Terminal locations at the service tool connector
(A) +Battery
(B) −Battery
(C) CAN data link global shield
(D) Cat Data Link +
(E) Cat Data Link −
(F) CAN data link global −
(G) CAN data link global +
Illustration 3 g03383124
Terminal locations at the P1 ECM connector that are for the data links
(P1-8) Cat Data Link +
(P1-9) Cat Data Link −
(P1-34) Global CAN data link −
(P1-42) Global CAN shield
(P1-50) Global CAN data link +
(P1-52) +Battery
(P1-53) +Battery
(P1-55) +Battery
(P1-57)