CASE 2H9398 - Caterpillar

Illustration 1 g01273912
Schematic of the Fuel Level SenderThis diagnostic code is associated with the fuel level sender. The FMI 4 means that the ECM has determined that the voltage of the circuit for the position sender is below normal. The possible causes of this diagnostic code are listed:
The signal circuit for the sender is shorted to ground.
The sender has failed.
The ECM has failed. ECM failure is unlikely. 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 this diagnostic code 96-4 is active before performing this procedure. Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.Test Step 1. CHECK THE SENDER
Turn the key start switch to the ON position.
Ensure that the diagnostic code is active.
Observe the status of the diagnostic code. Disconnect the sender from the machine harness.Expected Result:The 96-4 code remains active.Results:
OK - The diagnostic code remains active. The sender is correct. Proceed to Test Step 2.
NOT OK - The diagnostic code is no longer active. The sender has failed.Repair: Replace the sender.STOPTest Step 2. CHECK THE WIRING HARNESS OF THE SENDER FOR A SHORT TO GROUND
Disconnect the negative battery cable and turn the key start switch to the OFF position.
Disconnect the machine harness from the sender.
Disconnect the machine harness connector(s) from the monitor.
At the machine harness connector, measure the resistance from the signal contact 1 (wire 469-GN) of the machine harness to all possible sources of ground. Measure the resistance to all contacts of the machine harness connectors.Expected Result:Each resistance measurement is greater than 5000 ohms.Results:
OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 3.
NOT OK - One or more of the resistance measurements are not correct. There is a short in the machine harness.Repair: The short is between signal contact 1 (wire 469-GN) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS
Inspect the contacts of the harness connectors and clean the contacts.
Reconnect all harness connectors.
Reconnect the negative battery cable and turn the key start switch to the ON position.
Operate the machine.
Check the status of the 96-4 code.Expected Result:The 96-4 code is active. Results:
YES - The 96-4 code is active. The diagnostic code has not been corrected. The ECM may have failed.Repair: Perform this procedure again. Use Cat ET and perform a "Wiggle Test" on the machine wiring harness. Refer to Testing and Adjusting, KENR5119, "Electrical Connector - Inspect". The wiggle test may detect momentary or intermittent shorts and opens in the machine wiring harness. If all possible causes of the problem have been investigated and no problem can be found, you may need to replace the ECM. Prior to replacing an ECM, always contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time and expense. If the