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| Illustration 1 | g01238171 |
Schematic of the transmission oil temperature sensor | |
This diagnostic trouble code is associated with the transmission oil temperature sensor. The FMI 16 means that the ECU has determined that the oil temperature is above a normal operational range. The temperature could cause severe damage. The ECU reads the resistance from the sensor. A high oil temperature will send a low voltage to the ECU. The high temperature sends a voltage that is lower than the expected result for the ECU.
The cause of this diagnostic trouble code is listed:
- The oil temperature has reached 121° ± 8°C (250° ± 14°F).
The conditions that enable this diagnostic trouble code are listed:
- The oil level is below the correct level.
- An obstruction is keeping the oil cooler from performing properly.
- The voltage from the sensor is resisted.
Note: The temperature sensor consistently displays a severely high temperature. There is no problem with the wires or harness connections. The temperature sensor may have failed. Perform the following test steps in order to ensure that the problem is corrected.
Test Step 1. INSPECT THE HARNESS CONNECTIONS.
- Turn the disconnect switch to the OFF position.
- Check the connectors for proper mating.
- Check the wires at the connector.
- Check each wire for nicks or signs of abrasion in the insulation.
- Check for moisture at the connector.
- Check the connectors for dirty contacts or corroded contacts.
- Check each pin and each socket of the machine harness connectors.
Expected Result:
The machine harness connectors are tight and free of corrosion.
Results:
- OK - The machine harness connectors are tight and free of corrosion. Proceed to test step 2.
- NOT OK - The machine harness connectors are in need of repair.
Repair: Repair the machine harness or replace the machine harness.
STOP
Test Step 2. VERIFY THE TEMPERATURE OF THE OIL.
Check the temperature of the oil. Turn the engine OFF. Wait for 10 minutes. The oil pan for the transmission should be the same temperature as the oil. Use a heat gun in order to take a measurement of the temperature of the oil pan for the transmission.
Results:
- OK - The temperature of the oil is correct. Proceed to Test Step 3.
- NOT OK - The temperature of the oil is not correct.
Repair: Stop the engine until the oil temperature returns to an acceptable range.
STOP
Test Step 3. CHECK IF THE DIAGNOSTIC TROUBLE CODE REMAINS.
- Inspect the harness connectors. Clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, battery acid, or chafing.
- Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.
- Reconnect all harness connectors. Make sure that the harness connectors are fully seated and that the clips for each connector are completely fastened.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the vehicle.
- Check the status of the SPN 177 FMI 16.
Expected Result:
The SPN 177 FMI 16 is active.
Results:
- YES - The SPN 177 FMI 16 is active. The diagnostic trouble code has not been corrected.
Repair: Check the circuit again. It is unlikely that the ECU has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic trouble code is not found, replace the ECU. Prior to replacing an ECU, always contact your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. See Testing and Adjusting, "Electronic Control Unit - Replace".
STOP
- NO - The SPN 177 FMI 16 is not active. The diagnostic trouble code does not exist at this time. The initial diagnostic trouble code was probably caused by an elevated oil temperature that is no longer present.STOP