SEAL-LIP TYPE 8T9592 - Caterpillar

System Operation Description:The CAT data link is used for communication between electronic modules. The CAT data link is used to communicate information from the Electronic Control Module (ECM) to the Electronic Monitoring System (EMS). The CAT data link is used for programming and troubleshooting the ECM.The ECM communicates with the EMS in order to share engine information and diagnostics that may affect engine operation.The ECM communicates with the Caterpillar Electronic Technician (ET) in order to share status and diagnostic information. Cat ET can also be used to configure the ECM parameters on the engine. This information will not be available if communications fail between the ECM and Cat ET.
Illustration 1 g01041707
SchematicTest Step 1. Check for Connector Damage.
Turn the keyswitch to the OFF position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the ECM connectors (allen head screw) for the proper torque of 6 1 N m (53 9 lb in).
Check the harness and the wiring for abrasion and for pinch points.Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The connectors and wiring are okay. Proceed to Test Step 2.
Not OK - The connectors and/or wiring need repair.Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring. Stop.Test Step 2. Check for Electrical Shorts in the Harness.
Disconnect the ECM connectors for the ECM.
Disconnect any module that is connected to the CAT data link.
Measure the resistance at the following points. Wiggle the harness during the measurement in order to reveal an intermittent short.
CAT data link + to CAT data link -
CAT data link + to -Battery terminal
CAT data link - to -Battery terminal
CAT data link + to +Battery terminal
CAT data link - to +Battery terminal
CAT data link + to engine ground
CAT data link - to engine groundExpected Result:The resistance is more than 20,000 Ohms for each measurement.Results:
OK - The resistance is greater than 20,000 Ohms. Proceed to Test Step 3.
Not OK - The resistance is less than 20,000 Ohms. There is a short in the harness or in the connectors.Repair: Repair the connector and/or wiring or replace the connector and/or wiring. Stop.Test Step 3. Check the Resistance through the Harness for an Open Circuit.
Disconnect the ECM connectors for the ECM.
Disconnect any module that is connected to the CAT data link.
Short the wires of the CAT data link together. Create the short at P1:9 and P1:8 of the ECM connector.
Set an ohmmeter on the 200 Ohm scale. Measure the resistance between the terminals of the CAT data link + and the CAT data link -. Measure the resistance at the connectors for the ECM. Measure the resistance between the terminals of any module that was connected to the CAT