BUCKET AS-ROCK 5V5464 - Caterpillar

Possible causes for an FMI 3 Diagnostic code are:
The return circuit is open.
The signal circuit is open or the sensor is disconnected.
The signal circuit is shorted to another circuit.
The sensor has failed.
The ECM has failed. An ECM failure is unlikely.Possible causes for an FMI 4 Diagnostic code are:
The signal circuit for the sensor is shorted to ground.
The sensor has failed.
The ECM has failed. An ECM failure is unlikely.
Table 3
Temperature Sensor Output Resistance (Ohms)
-25 °C (-13 °F) 13052.6
-20 °C (-4 °F) 9716.7
-15 °C (5 °F) 7302.3
-10 °C (14 °F) 5538.0
-5 °C (23 °F) 4236.7
0 °C (32 °F) 3268.3
5 °C (41 °F) 2541.5
10 °C (50 °F) 1991.4
15 °C (59 °F) 1571.9
20 °C (68 °F) 1249.5
25 °C (77 °F) 1000.0
30 °C (86 °F) 805.5
35 °C (95 °F) 652.8
40 °C (104 °F) 532.3
Illustration 2 g03545525
Schematic of the Analog Passive circuits
Note: The diagram above is a simplified schematic of the connections for the sensor signal (analog passive) circuits. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of the Electrical Schematic, UENR6727 for the complete schematic.Diagnostic Code Troubleshooting Procedure
Note: Prior to beginning this procedure, inspect the harness connectors that are involved in this 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 the diagnostic code is active before performing a troubleshooting procedure.
Table 4
Troubleshooting Test Steps Values Results
1. Identify The Active DTC Code Associated With The Suspect Circuit
Code present. FMI 3 diagnostic code, proceed to Test Step 2.
FMI 4 diagnostic code, proceed to Test Step 5.
Begin Process For FMI 3 Troubleshooting HERE
2. Check The Sensor
Note: See Table 3 for a list of resistances related to specific temperature values. The maximum resistance for the sensor is 33,650 Ω, the minimum is 51.2 Ω.
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 Table 3. OK - The resistance reading agrees with the values in 3.
Proceed to Test Step 3.
NOT OK - The resistance reading does not agree with the values in 3.
Repair: Replace the sensor.
STOP
3. 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. Disconnect the J1 and J2 connectors from the ECM.
D. At the harness connector for the sensor install a jumper wire.
E. At the harness connector for the ECM measure the resistance at the contacts for the sensor.
The resistance reading is less than 5 Ω. OK - The resistance is less than 5 Ω.
Proceed to Test Step 4.
NOT OK - The resistance is greater than 5 Ω.
Repair: Either the signal or the return circuit wire is open. Repair or replace the harness.
STOP
4.