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| Illustration 1 | g02579763 |
Schematic of the cylinder position sensor (Apron control) | |
This diagnostic code is associated with the Cylinder Position Sensor (Apron Control). The FMI 08 means that the ECM has determined that the signal frequency or the signal pulse width is not within the expected range.
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 sensor has failed.
- Intermittent connections or poor connections.
- Mechanical devices are loose.
- 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 3497 FMI 08 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 all commands for the apron to be disabled.
Note: When this diagnostic code goes away, the operator must move the lever for the apron to the neutral position for 2 seconds before commands will be allowed.
Test Step 1. 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 7X-1710 Multimeter Probe along the voltage supply wire (contact A).
- Turn the key start switch and the disconnect switch to the ON position.
- Measure the voltage from contact A to frame ground.
Expected Result:
The voltage is 8 VDC.
Results:
- OK - The voltage is 8 VDC. Proceed to Test Step 3.
- NOT OK - The voltage is not 8 VDC. The circuit is open.
Repair: Repair the machine harness or replace the machine harness.
STOP
Test Step 2. CHECK THE SIGNAL CIRCUIT OF THE SENSOR
- Turn the key start switch and the disconnect switch to the OFF position.
- At the back of the harness connector for the sensor, remove the 7X-1710 Multimeter Probe from contact A and insert the probe along the signal wire (contact C).
- At the back of the harness connector for the sensor, insert the 7X-1710 Multimeter Probe along the ground wire (contact B).
- Turn the disconnect switch and the key start switch to the ON position.
- Monitor the signal of the sensor with the 146-4080 Digital Multimeter .
- Without disconnecting the sensor or the hardware that is associated with the sensor from the machine, take the sensor through the full operating range of the sensor.
Note: On some machines, it may be necessary to start the engine in order to take the sensor through the full operating range of the sensor.
Expected Result:
The signal of the sensor is 500 Hz ±150Hz.
Results:
- OK - The signal of the sensor responds correctly. The sensor is operating correctly. Proceed to Test Step 3.
- NOT OK - The signal of the sensor does not respond correctly. The sensor is NOT operating correctly.
Repair: Replace the sensor.
STOP
Test Step 3. CHECK THE SIGNAL CIRCUIT AT THE ECM
- Turn the key start switch and the disconnect switch to the OFF position.
- Insert the 7X-1710 Multimeter Probes into the back of the ECM connector along J2-17 (wire R845-GY) and J1-45 (wire P770-WH).
- Turn the disconnect switch and the key start switch to the ON position.
- Monitor the signal of the sensor with the 146-4080 Digital Multimeter .
- Without disconnecting the sensor or the hardware that is associated with the sensor from the machine, take the sensor through the full operating range of the sensor.
Note: On some machines, it may be necessary to start the engine in order to take the sensor through the full operating range of the sensor.
Expected Result:
The signal of the sensor is 500 Hz ±150Hz.
Results:
- OK - The signal of the sensor responds correctly. The sensor is operating correctly. Proceed to Test Step 4.
- NOT OK - The signal of the sensor does not respond correctly. The harness has failed.
Repair: Repair the machine harness or replace the machine harness.
STOP
Test Step 4. CHECK THE SIGNAL CIRCUIT FOR A SHORT IN THE HARNESS
- The key start switch and the disconnect switch remain in the OFF position.
- Disconnect the machine harness connectors from the sensor and the ECM.
- Measure the resistance between contact J2-17 (wire R845-GY) and all contacts that are used in the machine harness connectors for the ECM.
Expected Result:
The resistance is greater than 5000 ohms.
Results:
- OK - The resistance is greater than 5000 ohms. The circuit is correct. Proceed to Test Step 5.
- NOT OK - The resistance is less than 5 ohms. The signal circuit is shorted to another circuit in the harness.
Repair: Repair the machine harness or replace the machine harness.
STOP
Test Step 5. CHECK IF THE DIAGNOSTIC CODE REMAINS
- Inspect the harness connectors and clean the contacts of the machine harness connectors.
- 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 3497 FMI 08.
Expected Result:
The CID 3497 FMI 08 is not active.
Results:
- OK - The CID 3497 FMI 08 is not active. The diagnostic code does not exist at this time. The initial diagnostic code was probably caused by a poor connection or a short at one of the connectors that was disconnected and reconnected. Resume normal operation.STOP
- NOT OK - The CID 3497 FMI 08 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 the Testing and Adjusting, "Electronic Control Module (ECM) - Replace" section of this manual for additional information.
STOP