CRANKSHAFT-AIR COMPRESSOR 4W9476 - Caterpillar

Illustration 1 g02031734
Schematic of the Cat Data Link CircuitThis diagnostic code is recorded when the Machine ECM does not receive the expected information from the Engine ECM.The likely possible causes of this diagnostic code are listed below:
The software that is installed on the Engine ECM is incorrect.
The software that is installed on the Machine ECM is incorrect.System Response:When this diagnostic code is active, the following occurs:
Engine shutdown due to diagnostic feature is disabled.
Loss of engine data over Cat Data Link.
Operator station fault lamp is active.
The following pop-up message shows on graphical display: "Loss of communication with Engine. Engine features may be disabled."Test Step 1. VERIFY THE HARDWARE AND THE SOFTWARE PART NUMBERS.
Verify that the following information is correct:
The part number of the software of the Machine ECM
The part number of the Engine ECM software
The part number of the Machine ECM
The part number of the Engine ECM Note: Consult the Business Unit that produces the product for the correct part numbers of the configuration software.Expected Result:All part numbers are correct. Results:
OK - All part numbers are correct. Proceed to Test Step 2.
NOT OK - All part numbers are NOT correct. The part number of the Machine ECM may be incorrect. The part number of the Engine ECM may be incorrect. The incorrect configuration software may also be installed. Repair: Replace the incorrect ECM with an ECM that has the correct part number. Flash the correct configuration software. See Troubleshooting, "Electronic Control Module - Flash Program".STOPTest Step 2. INSPECT THE HARNESS CONNECTIONS.
Turn the disconnect switch to the OFF position.
Inspect all harness connections that are related to the Cat Data Link. Make sure that the connectors are clean and tight.
Check the connectors for proper mating.
Check the wires at the connector.
Check each wire for nicks or signs of abrasion in the insulation.
Check for moisture at the connector.
Check the connectors for dirty contacts or corroded contacts.
Check each pin and check each socket of the machine harness connectors. Expected Result:The machine harness connectors are tight and free of corrosion. Results:
OK - The machine harness connectors are tight and free of corrosion. Proceed to Test Step 3.
NOT OK - The machine harness connectors are in need of repair.Repair: Repair the machine harness or replace the machine harness. STOPTest Step 3. CHECK FOR SHORTS TO GROUND.
The disconnect switch remains in the OFF position.
Disconnect the machine harness from all electronic control modules that use the Cat Data Link.
At the machine harness for the Machine ECM, measure the resistance between frame ground and connector contacts J2-16 (wire 892-BR) and J2-25 (wire 893-GN) of the Cat Data Link circuit. Expected Result:The resistance is greater than 5000 ohms. Results:
OK - The resistance is greater than 5000 ohms. The harness circuit resistance is correct. Proceed to Test Step 4.
NOT OK - The resistance is less than 5000 ohms. The machine harness has failed. Repair: There is a short between frame ground and the Cat Data Link circuit in the machine harness. Repair the machine harness or replace the machine harness. STOPTest