HEAD-CYL. 5B8346 - Caterpillar

Table 3
FMI 4 Troubleshooting
Troubleshooting Test Steps Values Results
1. Check The Sensor
A. Turn the disconnect switch and the key start switch to the ON position.
B. Disconnect the sensor from the machine harness.
C. Observe the status of the diagnostic code as the sensor is disconnected from the harness.
The code changes from an FMI 4 to an FMI 3 when the sensor is disconnected. OK - The code changes from an FMI 4 to an FMI 3 when the sensor is disconnected. The sensor has failed.
Repair: Replace the sensor.
Proceed to Test Step 3.
NOT OK - The FMI 4 diagnostic code remains active when sensor is disconnected. The sensor is not the cause of the problem.
Proceed to Test Step 2.
2. Check The Signal Circuit For A Short To Ground
A. Turn the key start switch and the disconnect switch to the OFF position.
B. Disconnect the harness connectors from the ECM. The sensor remains disconnected from the machine harness.
C. At the ECM harness connector, measure the resistance between the sensor signal contact and all possible sources of ground.
All resistance values are greater than 5K Ω. OK - All resistance values are greater than 5K Ω. The harness circuit is correct.
Proceed to Test Step 3.
NOT OK - One or more readings are less than 5 Ω. A short circuit exists between the signal circuit .
Repair: Repair or replace the machine harness.
Note: A resistance greater than 5 Ω but less than 5K Ω indicates a loose or corroded connection in the circuit. A resistance measurement greater than 5K Ω indicates an open in the circuit.
Proceed to Test Step 3.
3. Check If The Diagnostic Code Remains
A. Reconnect all harness connectors. Return machine to normal operating condition.
B. Turn the key start switch and the disconnect switch to the ON position.
C. Clear all diagnostic codes.
D. Operate the machine.
E. Stop the machine and engage the safety lock .
F. Check if the diagnostic code is active.
The diagnostic code is no longer present. OK - The diagnostic code does not exist currently. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation.
STOP.
NOT OK - The diagnostic trouble code has not been corrected. If the diagnostic code has not been corrected after performing the procedure a second time, the ECM may require replacement.
Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may effect repair time.
Follow the steps in Troubleshooting, "ECM - Replace" if the ECM needs to be replaced.
STOP.
Table 4
FMI 8 Troubleshooting
Troubleshooting Test Steps Values Results
1. Check The Signal Of The Sensor
A. Turn the key start switch and disconnect switch to the OFF position.
B. At the back of the harness connector for the sensor, insert multimeter probes along the signal contact and return contact.
Note: Use Cat® Electronic Technician (Cat ET) Service Tool if access to the sensor when operating the machine, is not safe.
C. Turn the disconnect switch and the key start switch to the ON position.
D. Monitor the