BRACKET 1838237 - Caterpillar

Illustration 1 g00568117
(1) Safety cables.
Illustration 2 g00580712
Transmission Control Valve
(2) Latching Pressure Sensor (Transmission).
The location for the latching pressure sensor is on the transmission control valve that is mounted to the transmission.
Illustration 3 g00877338
Schematic Of The Latching Pressure Sensor
This diagnostic code is associated with the Latching Pressure Sensor (Transmission). The FMI 04 means that the ECM has determined that the voltage of the circuit for the position sensor is below normal. The output frequency of the sensor is approximately 5000 1500 Hz. The duty cycle of the signal varies and the duty cycle of the PWM signal is proportional to the pressure that is applied. The duty cycle varies from 10% to 90%.The possible causes of this diagnostic code are listed below:
The signal circuit for the sensor is shorted to ground.
The sensor has failed.
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 1233 FMI 04 is active before performing this procedure. Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.
When it is necessary to work under the machine with the body (bed) raised, attach the body (bed) retaining cables to the rear tow points. Install the rear tow point pins through the ends of the retaining cables.Failure to properly secure the body (bed) may result in personal injury or death.
Test Step 1. CHECK THE SENSOR
Turn the disconnect switch and the key start switch to the ON position.
Ensure that the diagnostic code is active.
Observe the status of the diagnostic code. Disconnect the sensor from the machine harness. Expected Result:The CID 1233 FMI 04 remains active. The FMI has not changed and the "04" is still active.Results:
OK - The diagnostic code remains active. The sensor is correct. Proceed to Test Step 2.
NOT OK - The diagnostic code is no longer active. The sensor has failed.Repair: Replace the sensor.STOPTest Step 2. CHECK THE WIRING HARNESS OF THE SENSOR FOR A SHORT TO GROUND.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness from the sensor.
Disconnect the machine harness connector(s) from the ECM.
At the machine harness connector for the ECM, measure the resistance from the signal contact J1-62 (wire J823-CF23-YL(Yellow)) of the machine harness to all possible sources of ground. Measure the resistance to all contacts of the machine harness connectors for the ECM. Expected Result:Each resistance measurement is greater than 5000 ohms.Results:
OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 3.
NOT OK - One or more resistance measurements is not correct. There is a short in the machine harness. Repair: The short is between signal contact J1-62 (wire J823-CF23-YL(Yellow)) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS.
Inspect the contacts of the harness connectors