CORE AS-AFTERCOOLER 7W5456 - Caterpillar

System Operation Description:The Cat data link is used to share information between the following components:
Master Electronic Control Module (ECM)
Slave ECM
Integrated Temperature Sensing Module (ITSM)
Service tool
Customer installed componentsIllustration 1 shows the information that is shared between the master ECM and the slave ECM via the Cat data link.
Illustration 1 g00951847
Each ECM and the ITSM communicate with Cat ET via the Cat data link. The Cat data link consists of two wires that are twisted together. One wire is designated as +. The other wire is designated as -. The signals on the data link wires are a square wave type signal. The signals operate at a very high frequency. The signals cannot be measured with common service tools. Therefore, only continuity measurements can be made on the wires for the Cat data link.The most likely cause of a diagnostic code for the Cat data link are an open circuit or a short circuit. Connector terminals that are not fully seated in the connector body can create an open circuit condition. Be careful not to interchange the + wire and the - wire in a connector. The Cat data link will not operate if the + wire and the - wire are interchanged in a connector.The Cat data link can fail if a module is not receiving power. This can happen if there is a problem with the wiring that provides power to the module.The Cat data link can fail if a module is programmed with the wrong FLASH file, or if a module has not been programmed with a FLASH file. Verify that all modules have been programmed with the proper FLASH file.Harness Code for the Slave ECMThe harness inside the terminal box has a jumper wire (harness code) that connects terminals J3-29 and J3-60. The ECM that is connected to the harness reads the harness code. This allows the ECM to operate as the slave ECM.If the jumper wire is disconnected, the slave ECM will assume the function of a master ECM. Cat ET will not communicate with any of the modules. Cat ET will display "DupliCate Type on data link. Unable to Service".
Illustration 2 g00994089
Schematic diagram of the Cat data linkTest Step 1. Inspect the Electrical Connectors and wiring
Set the engine control to the OFF/RESET mode. Switch the 16 amp circuit breaker OFF.Note: For the following steps, refer to Troubleshooting, "Inspecting Electrical Connectors".
Illustration 3 g00920000
Terminal box for the master ECM (1) Ground strap (2) J1/P1 connectors for the master ECM (3) J23 connector for Cat ET (4) J19 connector (5) 16 amp circuit breaker (6) J5/P5 connectors for the harness to the ITSM (7) J8/P8 connectors for the harness to the slave ECM (8) J9/P9 connectors
Illustration 4 g00920005
Terminal box for the slave ECM (9) J3/P3 connectors for the slave ECM (10) J20/P20 connectors for the harness to the master ECM
Illustration 5 g00920007
ITSM (11) ITSM (12) J18/P18 connectors for the harness to the terminal box for the master ECM
Thoroughly inspect each of the following connectors:
Master ECM J1/P1 connectors
J23, J5/P5, J8/P8, J9/P9 and J19