SEAL 0773790 - Caterpillar

Which Generate This Code:This diagnostic code is associated with the CAT Data Link. The FMI 02 means that the ECM has not received expected information. The information from the CAT Data Link indicates the abnormal values in the readout.The possible causes of this diagnostic code are:
Poor electrical connection at a machine harness connector.
The circuit for the CAT Data Link in the machine harness is shorted to ground.
The circuit for the CAT Data Link in the machine harness is shorted to the +battery.
The circuit for the CAT Data Link in the machine harness is open.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0248 FMI 02 is active before performing this procedure.Test Step 1. INSPECT THE HARNESS CONNECTORS
Turn the disconnect switch and key start switch to the OFF position.
Inspect the connections for the machine harness that are related to the CAT Data Link.
Make sure that connectors are clean and tight.Expected Result:The machine harness is correct.Results:
YES - The machine harness is correct. Proceed to Test Step 2.
NO - The machine harness is not correct.Repair: Repair the machine harness or replace the machine harness.STOPTest Step 2. CHECK FOR A SHORT TO GROUND
The disconnect switch and key start switch remain in the OFF position.
Disconnect the machine harness from all the electronic control modules that use the CAT Data Link.
At the machine harness connector for the Power Train ECM, measure the resistance between frame ground and the circuits of the CAT Data Link, contacts J1-20 (wire 892-BR)