LINE-F INJ-YM 3731888 - Caterpillar

Note: The following procedure checks for incorrect harness codes on the inputs for the main display module. Compare the status of the harness code that is found in the test "Determine the machine code" to the status at the inputs for the main display module. The table identifies the connector contacts and wire identification of the harness code circuits. Contacts that are specified as grounded contacts should be checked for opens in the harness. Contacts that are specified as open contacts should be checked for shorts in the harness.Test Step 1. CHECK FOR OPENS
Turn the disconnect switch to the OFF position.
Disconnect the machine harness from the main display module.
Check for continuity between the connector contacts that are grounded contacts and contact 2 (ground). Check for continuity at the machine harness connector for the main display module.Expected Result:The resistance measures 5.0 Ohms or less.Results:
YES - The resistance is 5.0 Ohms or less. The circuit for the harness code is not open. No defect was found in the ground circuits for the harness code. Proceed to test step 2.
NO - The resistance is greater than 5.0 Ohms. The circuit for the harness code is open. Check the harness code plug on so equipped machines. Record the open contact of the machine harness connector.Repair: Repair the open circuits for the harness code that is found or replace the machine harness. If conditions are not resolved, proceed to test step 2.Test Step 2. CHECK FOR SHORTS
The disconnect switch remains in the OFF position. The machine harness to the main display module remains disconnected.
Measure the resistance between the connector contacts that are specified as open contacts and contact 2 (ground). Measure the resistance at the machine harness connector for the main display module.Expected Result:The resistance measures 5000 Ohms or more.Results:
YES - The resistance is 5000 Ohms or more. The circuit for the harness code is not shorted to ground. No defect was found in the circuit for the harness code.STOP
NO - The resistance is less than 5000 Ohms. The circuit for the harness code is shorted. Check the harness code plug on so equipped machines. Record the shorted contact of the machine harness connector.Repair: Repair the shorted circuits of the harness code that are found or replace the machine harness. If conditions are not resolved, proceed to test step 3.Test Step 3. CHECK IF THE PROBLEM REMAINS
Reconnect the harness connectors.
Turn the disconnect switch and the key start switch to the ON position.
Recheck the machine code.Expected Result:The main display module shows the correct machine code.Results:
YES - The main display module shows the correct machine code.STOP
NO - The main display module does not show the correct machine code. Replace the module.Repair: It is unlikely that the module has failed. Exit this procedure and perform this diagnostic code procedure again. If the problem has not been found, then replace the main display module. See Testing and Adjusting, "Module - Replace".STOP