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| Illustration 1 | g02579780 |
Schematic of the cylinder position sensor (Bowl control) | |
This diagnostic code is associated with the Cylinder Position Sensor (Bowl Control). 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 position sensor is approximately 500 Hz. The duty cycle of the signal changes as the position sensor moves.
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. The failure of ECM 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 3498 FMI 04 is active before performing this procedure.
Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.
System Response:
When this diagnostic code occurs, a warning (Category 1) is shown on the monitor. The diagnostic code will cause the solenoids for the bowl control to be set to the minimum command. Control of the bowl will not return until the diagnostic code is inactive. The signal from the position sensor must be in the neutral position for at least 2 seconds.
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 3498 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- NOT OK - The diagnostic code is no longer active.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.
STOP
Test 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 J2-18 (wire R846-PK) 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 measurement or more resistance measurement is not correct. There is a short in the machine harness.
Repair: The short is between signal contact J2-18 (wire R846-PK) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.
STOP
Test Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS
- Inspect the contacts of the harness connectors and clean the contacts.
- Reconnect all harness connectors.
- Turn the disconnect switch and the key start switch to the ON position.
- Operate the machine.
- Check the status of the CID 3498 FMI 04.
Expected Result:
The CID 3498 FMI 04 is active.
Results:
- YES - The CID 3498 FMI 04 is active. 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, the ECM may have failed. Prior to replacing an ECM, always contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, See Testing and Adjusting, "Electronic Control Module (ECM) - Replace" section of this manual for additional information.
STOP
- NO - The CID 3498 FMI 04 is not active. The diagnostic code does not exist at this time.
Repair: 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 reconnected. Resume normal machine operation.
STOP