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| Illustration 1 | g01254084 |
Schematic of the transmission oil pressure sensor | |
This diagnostic code is associated with the transmission oil pressure sensor. The FMI 04 means that the ECM has determined that the voltage of the pressure sensor as being below normal. The pressure sensor is a component that produces a PWM output.
The output frequency of the sensor is approximately 5000 Hz. The duty cycle of the signal varies as the pressure sensor moves.
The possible causes of this diagnostic code are:
- A shorted harness.
- A failed sensor.
- The ECM may have 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 0127 FMI 04 is active before performing this procedure.
System Response:
The oil pressure for the transmission is unknown. The ECM will engage the parking brake. The parking brake will operate properly when the diagnostic code is corrected.
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 present.
- Observe the status of the diagnostic code. Then, disconnect the machine harness from the sensor.
Expected Result:
If the sensor is not the cause of the diagnostic code, the diagnostic code remains present. If the sensor has failed, the diagnostic code is NO longer present.
Results:
- YES - The diagnostic code remains present. The sensor is not faulty. The machine harness or the ECM may be faulty. Proceed to Test Step 2.
- NO - The diagnostic code is NO longer present.
Repair: The machine harness is correct and the ECM is operating properly. The sensor has failed. Replace the sensor.
STOP
Test Step 2. CHECK THE SIGNAL CIRCUIT FOR A SHORT TO GROUND
- The sensor remains disconnected from the machine harness.
- Turn the disconnect switch and the key start switch to the OFF position.
- Disconnect the machine harness from the ECM.
- Measure the resistance from J2-25 wire (X730-BR) to all possible sources of ground.
Expected Result:
The resistance is greater than 5 ohms.
Results:
- YES - The resistance is greater than 5 ohms. The machine harness is correct. Proceed to Test Step 3.
- NO - The resistance is less than 5 ohms. The machine harness has failed.
Repair: Repair the machine harness or replace the machine harness.
STOP
Test Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS
- Clean the contacts of the harness connectors.
- Reconnect all harness connectors.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the machine.
- Observe the status of the diagnostic code.
Expected Result:
The CID 0127 FMI 04 diagnostic code is present.
Results:
- YES - The diagnostic code has not been corrected. The ECM may have failed.
Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. Refer to Troubleshooting, Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP
- NO - The diagnostic code is NOT present. The diagnostic code does not exist at this time. The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was disconnected and then reconnected. Resume normal machine operation.STOP