Conditions Which Generate This Code:
Schematic of the Left Hand Joystick Position Sensor (Base)
This diagnostic code is associated with the forward-rearward location for the base of the left joystick. Each sensor provides an input signal to the ECM. This diagnostic code is recorded when the ECM determines the signal from the sensor and the voltage of the signal is below normal.
The position sensor is a PWM sensor that operates at a frequency of approximately 500 ± 80 Hz. The duty cycle of the signal will vary from approximately 20% at the full rearward position of the joystick to approximately 80% at the full forward position of the joystick. When the joystick is in the center position, the duty cycle will be approximately 50%.
The possible causes of this diagnostic code are listed:
- The signal circuit is shorted to ground.
- The sensor has failed.
- The ECM has failed. ECM failure is unlikely.
Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected. Verify that CID 2474 FMI 04 is active before performing this procedure.
Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean. Verify that all connections in the circuit are secure. Verify that all connections in the circuit are in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.
The diagnostic will generate a level 2 warning. The machine will be brought to a stop. The parking brake will remain engaged until the diagnostic has been cleared. Also, the parking brake will remain engaged until the hystat lever has been returned to the neutral.
Test Step 1. CHECK THE SENSOR
- Turn the key start switch to the ON position.
- Disconnect the machine harness connector from the left joystick. Observe the status of the diagnostic code.
The FMI 04 diagnostic code will remain active if the sensor is not the cause of the problem. The sensor is internally shorted if the FMI 04 diagnostic code is NO longer active.
- OK - The FMI 04 diagnostic code remains active. The sensor has not failed. Proceed to Test Step 2.
- NOT OK - The FMI 04 diagnostic code is NO longer active. The machine harness and the ECM are operating correctly.
Repair: Inspect the harness at the sensor for any failures. Disconnecting the sensor could temporarily cause the short to be removed from the harness. Reconnect the sensor and verify that the diagnostic code has become active again. Repair or replace the harness for the left joystick. After replacement of the joystick, verify that the operation of the new joystick is correct before operating the machine.
Test Step 2. CHECK THE SIGNAL CIRCUIT FOR A SHORT TO GROUND
- The connector for the joystick must remain disconnected from the machine harness.
- Disconnect the negative battery cable and turn the key start switch to the OFF position.
- Disconnect the J1 and J2 machine harness connectors from the Machine ECM.
- At machine harness connector for the Machine ECM, measure the resistance from contact J1-71 (wire E848-GN) to frame ground and measure the resistance to all of the other J1 and J2 contacts that are used for the Machine ECM.
Each resistance measurement is greater than 5000 ohms.
- OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 3.
- NOT OK - One or more of the resistance measurements is NOT correct. The machine harness has failed.
Repair: There is a short in the machine harness between the signal circuit and the circuit with the low resistance measurement. Repair or replace the machine harness.
Test Step 3. CHECK THE STATUS OF THE DIAGNOSTIC CODE
- Inspect the harness connectors. Clean the contacts of the harness connectors. Check the wires for damage to the insulation. This damage is caused by excessive heat, corrosion, or chafing.
- Perform a 45 N (10 lb) pull test on each of the wires that are associated with the sensor circuit.
Reference Testing and Adjusting, "Electrical Connector - Inspect" in this manual
- Reconnect all harness connectors. Make sure that the connectors are fully seated. Make sure that the clips for each connector are fastened completely.
- Reconnect the negative battery cable and turn the key start switch to the ON position.
- Operate the machine.
- Determine if the CID 2474 FMI 04 diagnostic code is active.
The CID 2474 FMI 04 diagnostic code is not active.
- OK - The CID 2474 FMI 04 diagnostic code 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 2474 FMI 04 diagnostic code is active. The diagnostic code has not been corrected.
Repair: ECM failure is unlikely. Perform this procedure again.
If the cause of the diagnostic code is not found, contact your dealer Technical Communicator (TC) for possible consultation with Caterpillar. This consultation may greatly reduce repair time.
If the ECM requires replacement, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".