NUT 3C6969 - 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 engines Electronic Control Module (ECM) to the Electronic Monitoring System. The Cat Data Link is used for programming and troubleshooting the ECM. The Cat Data Link can be used to program the Engine ECM through FLASH downloading. This information will not be available if communications fail between the ECM and the Cat ET.
Illustration 1 g00903452
Note: The Engine Control Switch (ECS) is mounted within an instrument panel that is located on the right side of the engine. The ECS is locked into the AUTO position with a pin. The pin must be removed in order to perform this test. After performing this test, ensure that the ECS is placed in the AUTO position and that the locking pin has been reinstalled.Test Step 1. Check for Connector Damage.
Verify that the circuit breakers are not tripped.
Turn the circuit breaker for the battery to the OFF position.
Turn the ECS to the OFF/RESET position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.
Check the ECM connectors (allen head screw) for the proper torque of 6.0 N m (55 lb in).
Check the customer connectors (allen head screw) for the proper torque of 2.25 0.25 N m (20 2 lb in).
Check the harness and the wiring for abrasion and pinch points.Expected Result:All connectors, pins, and sockets are coupled and/or inserted, and the harness and wiring should be 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 are not okay.Repair: Repair the connectors or wiring and/or replace the connectors or wiring.STOPTest Step 2. Check the Cat Data Link.
Turn the ECS to the OFF/RESET position.
Connect the Cat ET.
Turn the circuit breaker for the battery to the ON position.
Turn the ECS to the STOP position.
Check for any LOGGED diagnostic codes.
Start the engine and read the status information on the Cat ET.
Observe the engine oil pressure and the coolant temperature on the Electronic Monitoring System.Note: If some of the parameters, but not all of the parameters were displayed, the Cat Data Link is okay. Check the component that is associated with any missing parameter.Expected Result:The Cat ET should display the status information. The Electronic Monitoring System should display engine parameters.Results:
OK - The Cat Data Link is operating correctly at this time.Repair: If the problem is intermittent, perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".STOP
No Parameter Displayed - There is a problem