PLUNGER A 4M4339 - Caterpillar

Illustration 1 g01143214
Schematic of the speed sensor (transmission output)
This diagnostic code is associated with the speed sensor (transmission output). The FMI 01 means that the ECM has determined that the signal from the transmission output speed sensor is below normal operating range. The transmission output speed sensor is a frequency sensor.The frequency signal increases as the speed increases.The possible causes of this diagnostic code are listed below:
The sensor has failed.
The signal circuit of the sensor is shorted to the ground.
The sensor needs to be adjusted.
The ECM has failed. This is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 0191 FMI 01 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.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:
YES - 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.
NO - 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 A SHORTED SENSOR
Turn the disconnect switch to the OFF position.
Disconnect the harness from the speed sensor.
At the sensor, measure the resistance between each connector contact and the case of the sensor. Expected Result:The resistance of either measurement is greater than 5 ohms.Results:
YES - Resistance of either measurement is greater than 5 ohms. Proceed to Test Step 3.
NO - Resistance of either measurement is less than 5 ohms. The sensor has failed.Repair: Replace the sensor. Install and adjust the speed sensor. Refer to Systems Operation, Troubleshooting, Testing and Adjusting, "Speed Sensor - Adjust" for the machine that is being serviced.STOPTest Step 3. CHECK THE RESISTANCE AT THE SENSOR
The disconnect switch remains in the OFF position and the speed sensor remains disconnected from the harness.
At the sensor, measure the resistance between the two contacts of the connector. Expected Result:The resistance should be approximately 1075 ohms.Results:
YES - Resistance is approximately 1075 ohms. Proceed to Test Step 4.
NO - Resistance is not approximately 1075 ohms. The sensor has failed.Repair: Replace the sensor. Install and adjust the speed sensor. Refer to Systems Operation, Troubleshooting, Testing and Adjusting, "Speed Sensor - Adjust" for the machine that is being serviced.STOPTest Step 4. CHECK FOR A SHORTED HARNESS
The disconnect switch remains in the OFF position and the speed sensor remains disconnected from the harness.
Disconnect the harness from the Power Train ECM.
At the harness connector for the Power Train ECM, measure the resistance between contact J1-2 (wire 710-GN(Green)) and all other