SPN 175 - FMI 4 (Diagnostic Code: Engine Oil Temperature Sensor - Voltage Below Normal)

SPN 175 FMI 4

SPN175 FMI4

Figure 1.1 - SPN 175 FMI 4 (Murphy PowerView)

MID 036 CID 175 FMI 04

CID 0175 FMI 04 Engine Oil Temperature Short to Ground

Conditions Which Generate This Code: 

The Electronic Control Module (ECM) has been powered for at least two seconds. The ECM reads signal voltage that is below 0.2 VDC for eight seconds.

System Response:

The ECM will log the Diagnostic Code. The Diagnostic Code may be viewed on a display module or on the Caterpillar Electronic Technician (ET), refer to the Figure 1.1 above. The ECM flags Engine Oil Temperature as invalid data (Voltage above/below normal). The ECM sets the Engine Oil Temperature to the same value as the Coolant Temperature. If the Coolant Temperature sensor has failed, one of the following values is used:

→If the Engine is running, the Engine Oil Temperature is set to 65 °C (149 °F).

→If the Engine is not running, the Engine Oil Temperature is set to −10 °C (14 °F).

Possible Performance Effect:

None

#Troubleshooting:

The troubleshooting procedures for the Diagnostic Codes of each temperature sensor are identical. The temperature sensors are passive sensors that have two terminals. The temperature sensors do not require supply voltage from the Electronic Control Module (ECM).

Test Step 1. Verify all Active Diagnostic Codes

A. Connect Caterpillar Electronic Technician (ET) to the service tool connector. Read More: How to Connecting Caterpillar ET Software to the ECM.

B. Place the Engine control in the ON mode. Wait at least 15 seconds for activation of the Diagnostic Codes.

C. Monitor the Active Diagnostic Codes screen on Cat ET.

Expected Result: There is an Active Diagnostic Code for the Engine Oil Temperature Sensor.

Figure 1.2 - Voltage Below Normal (175-4)

Test Step 2. Inspect Electrical Connectors and Wiring

A. Place the Engine control in the OFF/RESET mode.

B. Thoroughly inspect the J2/P2 ECM connector, the Engine Oil Temperature Sensor connector, and any other connectors in the circuit.

C. Perform a 45 N (10 lb) pull test on each of the wires in the Engine Oil Temperature Sensor connector and the ECM connector that are associated with the Active Diagnostic Code.

D. Verify that the latch tab of the connector is properly latched.

E. Check the ECM connector (allen head screw) for the proper torque.

F. Check the harness and wiring for abrasions and for pinch points from the sensor to the ECM. Expected Result: All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.

Test Step 3. Disconnect the Sensor in Order to Create an Open Circuit

A. Place the Engine control in the OFF/RESET mode.

B. Disconnect the connector to the Engine Oil Temperature Sensor with the short circuit Diagnostic Code 04.

C. Place the Engine control in the ON mode. Wait at least 15 seconds for activation of the Diagnostic Codes.

Figure 1.3 - SPN 175 FMI 3 (Murphy PowerView)

D. Access the Active Diagnostic Codes screen on Cat ET and check for an Active open circuit Diagnostic Code 03 for the Engine Oil Temperature Sensor.

Figure 1.4 - Voltage Above Normal (175-3)

E. Place the Engine control in the OFF/RESET mode.

Expected Results: An open circuit Diagnostic Code 03 is now active for the disconnected Engine Oil Temperature Sensor.

Results:

→OK - A short circuit Diagnostic Code 04 was active before disconnecting the sensor. An open circuit Diagnostic Code 03 became active after disconnecting the sensor.

→Repair - Temporarily connect a new sensor to the harness, but do not install the new sensor in the Engine. Check for a short circuit Diagnostic Code 04 while the new sensor is connected. If the short circuit Diagnostic Code 04 is not present, permanently install a new sensor (CAT P/N: 204-0320). Clear any Logged Diagnostic Codes. Verify that the repair eliminates the problem.

Read More:

Fuel Temperature Sensor - Voltage Above Normal (Diagnostic Code: SPN 174 - FMI 3)

Intake Manifold Air Temperature Sensor - Voltage Below Normal (Diagnostic Code: SPN 105 - FMI 4)

 

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