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| Illustration 1 | g01343143 |
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Connections of the position sensor (shift lever) | |
This diagnostic code is associated with the position sensor (shift lever). The FMI 8 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 hertz. The value of the sensor's duty cycle is approximately 50% in the neutral position. The duty cycle of the signal increases as the lever is moved from the neutral position to the forward position. The value of the sensor's duty cycle is approximately 80% ± 10% in the forward position. The duty cycle of the signal decreases as the lever is moved from the neutral position to the reverse position. The value of the sensor's duty cycle is approximately 20% ± 10% in the reverse position.
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. 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 SPN 1619 FMI 8 is active before performing this procedure.
Note: Use the digital multimeter for the measurements in this procedure.
System Response:
A warning will be displayed on the Caterpillar Electronic Technician (Cat ET). The transmission will be placed in the neutral gear until the diagnostic code is cleared.
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 multimeter probe along the voltage supply wire (contact 1).
- Turn the key start switch and the disconnect switch to the ON position.
- Measure the voltage from contact 1 to frame ground.
Expected Result:
The voltage is 10 DCV.
Results:
- OK - The voltage is 10 DCV. Proceed to Test Step 3.
- NOT OK - The voltage is not 10 DCV. 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 multimeter probe from contact 1 and insert the probe along the signal wire (contact 3).
- At the back of the harness connector for the sensor, insert the multimeter probe along the ground wire (contact 2).
- Turn the disconnect switch and the key start switch to the ON position.
- Monitor the signal of the sensor with the 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 sensor's signal responds in the manner that is described at the begining of this procedure.
Results:
- OK - The sensor's signal responds correctly. The sensor is operating correctly. Proceed to Test Step 3.
- NOT OK - The sensor's signal 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 multimeter probes into the back of the ECM connector along J1-26 and J1-9.
- Turn the disconnect switch and the key start switch to the ON position.
- Monitor the signal of the sensor with the 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 sensor's signal responds in the manner that is described at the begining of this procedure.
Results:
- OK - The sensor's signal responds correctly. The sensor is operating correctly. Proceed to Test Step 4.
- NOT OK - The sensor's signal 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 J1-26 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 SPN 1619 FMI 8.
Expected Result:
The SPN 1619 FMI 8 is not active.
Results:
- OK - The SPN 1619 FMI 8 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 SPN 1619 FMI 8 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 failure is not found, replace the ECM. See the Testing and Adjusting, "Electronic Control Module (ECM) - Replace".
STOP