SHIELD AS 4539223 - Caterpillar

Illustration 1 g03370228
Schematic of the Throttle Position Sensor
This diagnostic code is associated with the Throttle Position Sensor. The FMI 04 means that the ECM has determined that the voltage of the circuit for the position sensor is below normal. The throttle position control has an output frequency of approximately 500 Hz. The duty cycle of the signal changes as the throttle pedal position is changed. The duty cycle increases as the throttle pedal is depressed. The throttle pedal values are dependent on the throttle pedal linkage. Valid values range from 5% to 95% duty cycle.The possible causes of this diagnostic code are listed below:
Improperly adjusted throttle pedal linkage.
The signal circuit for the sensor is shorted to ground.
The sensor has failed.
The ECM has failed. The ECM is unlikely to fail.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 091 FMI 04 is active before performing this procedure.Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.System Response:The diagnostic code will generate a level 2 warning. Underspeed Control will be disabled and the hystat transmission will be limited to low speed.Test Step 1. Check The Output Of The Sensor
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the signal wire (contact F).
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the ground wire (contact B).
Turn the key start switch to the ON position.
Measure the duty cycle of the signal. The valid sensor range is 5% duty cycle to 95% duty cycle. This fault occurs for <5% duty cycle. Expected Result:The duty cycle is less than 5% for the whole range of the throttle pedal.Results:
OK - The duty cycle is less than 5% for the whole range of the throttle pedal. Proceed to Test Step 2.
NOT OK - The signal from the sensor is only invalid for part of the throttle pedal rangeRepair: The sensor is not adjusted correctly. Adjust the throttle pedal linkage so the sensor signal is valid through the entire range.STOPTest Step 2. Check The Sensor
The key start switch remains in 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 091 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 3.
NOT OK - The diagnostic code is no longer active or the FMI has changed from "04" to "03".Repair: Replace the sensor or repair the harness.STOPTest Step 3. Check The Wiring Harness Of The Sensor For A Short To Ground
Disconnect the negative battery cable and turn the key start switch to the OFF position.
Disconnect the machine harness from the sensor.
Disconnect the