HUB 1869372 - Caterpillar

Table 4
Fuel Level Sensor Resistance Values
Float Position Resistance (Ω)
Full 7.5 - 9
3/4 21
1/2 34
1/4 53
Empty 82 - 85 Diagnostic Trouble Code Procedure
Note: Prior to beginning this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.
Identify the active FMI code associated with the components.
Determine which code is present and use the list below to determine which procedure to follow.
FMI 3 diagnostic code, proceed to Table 5.
FMI 4 diagnostic code, proceed to Table 6.
Table 5
FMI 3 Troubleshooting
Troubleshooting Test Steps Values Results
1. Check The Sensor
Note: Refer to the appropriate table within this procedure for a list of resistance values related to the suspect sensor.
A. Turn the key start switch and the disconnect switch to the OFF position.
B. Disconnect the sensor from the harness.
C. Measure the resistance between pin 1 and 2 of the sensor.
The resistance reading agrees with the values from the table. OK - The resistance readings agree with the values in the specific table.
Proceed to Test Step 2.
NOT OK - The resistance readings do not agree with the values in the table.
Repair: Replace the sensor.
Proceed to Test Step 4.
2. Check For An Open In The Sensor Circuit
A. The key start switch and disconnect switch remain in the OFF position.
B. The harness connector remains disconnected from the sensor.
C. At the sensor harness connector, install a jumper wire across pins 1 and 2.
D. Disconnect the connectors from the ECM.
E. At the ECM harness connector, measure the resistance between the signal and return contacts for the sensor.
The resistance reading is less than 5 Ω. OK - The resistance is less than 5 Ω.
Proceed to Test Step 3.
NOT OK - The resistance is greater than 5 Ω. The open is in the signal circuit or the return circuit.
Repair: Repair or replace the harness.
Proceed to Test Step 4.
3. Check The Signal Circuit For A Short.
A. The disconnect switch and the key start switch remain in the OFF position.
B. The harness connectors remain disconnected from the ECM.
C. Remove the jumper wire from the sensor harness connector.
D. At the ECM harness connectors, measure the resistance between the signal circuit and all the other contacts on the ECM.
Each resistance reading is greater than 5K Ω. OK - Each measurement is greater than 5K Ω.
Proceed to Test Step 4.
NOT OK - A resistance measurement is less than 5 Ω. A short exists between the signal circuit and the circuit with the low-resistance measurement.
Repair: Repair or replace the machine harness.
Proceed to Test Step 4.
4. Check If The Diagnostic Code Remains
A. Reconnect all harness connectors. Return machine to normal operating condition.
B. Turn the key start switch and the disconnect switch to the ON position.
C. Clear all diagnostic codes.
D. Operate the machine.
E. Stop the machine and engage the