COVER 1U2074 - Caterpillar

Illustration 1 g01238171
Connections of the transmission oil temperature sensor
This diagnostic code is associated with the transmission oil temperature sensor. The FMI 0 means that the ECM has determined that the signal of the sensor is above the normal range.The output frequency of the position sensor is approximately 500 Hz. The value of the sensor duty cycle is approximately 3.5% when the pedal is released. The duty cycle of the signal increases as the pedal is moved from the released position to the pressed position. The value of the sensor duty cycle is approximately 96.5% in the pressed position. The possible causes of this diagnostic code are listed below:
The sensor has failed.
The signal circuit of the sensor is shorted to the + battery circuit.
The sensor needs calibrated.
The ECU has failed. The ECU failing is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of SPN 177 FMI 0 is active before performing this procedure.Note: Use the digital multimeter for the measurements in this procedure.System Response:A warning will be displayed on the Caterpillar Electronic Technician (Cat ET). The transmission will be placed in the neutral gear until the diagnostic code is cleared.Test Step 1. INSPECT THE SENSOR.
Perform a visual inspection of the sensor, the wiring for the sensor and the hardware that is associated with the sensor. Expected Result:There is no apparent damage to the sensor, the wiring for the sensor or the hardware that is associated with the sensor.Results:
OK - There is no apparent damage to the sensor, the wiring for the sensor or the hardware that is associated with the sensor. Proceed to Test Step 2.
NOT OK - There is apparent damage to the sensor, the wiring for the sensor or the hardware that is associated with the sensor. Repair: Replace the damaged part.Proceed to Test Step 8.Test Step 2. CHECK FOR POWER AT THE SENSOR.
Do not disconnect the harness connector from the sensor.
At the back of the harness connector for the sensor, insert a multimeter probe along the voltage supply wire (contact 1).
Turn the key start switch and the disconnect switch to the ON position.
Measure the voltage from contact 1 to frame ground. Expected Result:The voltage is 12 DCV.Results:
OK - The voltage is 12 DCV. Proceed to Test Step 3.
NOT OK - The voltage is not 12 DCV. The circuit is open. Repair: Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK FOR PROPER GROUND AT THE SENSOR.
The machine harness remains connected to the sensor.
Turn the key start switch and the disconnect switch to the OFF position.
Remove the multimeter probe from the voltage supply wire (contact 1).
At the back of the harness connector for the sensor, insert a multimeter probe along the ground wire (contact 2).
Measure the resistance from contact 2 to frame ground. Expected Result:The resistance is less than 5 ohms.Results:
OK - The resistance is less than 5 ohms. The ground