320E and 323E Excavators Machine Electronic Control System MID 299, 5226-3 Caterpillar

Conditions Which Generate This Code:

Illustration 1	g06011363
Schematic of "Swing Left Pilot Pressure" Sensor

This diagnostic code is associated with the "Swing Left Pilot Pressure" Sensor. The FMI 03 diagnostic code indicates that the Machine ECM is detecting a voltage for the pressure sensor that is above normal.

Conditions that can cause this diagnostic code to be activated are listed below:

• There is a problem with the sensor power supply.

• The signal circuit for the sensor has an open or a bad connection.

• The signal circuit for the sensor is shorted to a voltage source.

• The sensor has failed.

• The ECM has failed. An ECM failure is unlikely.

Note: When this diagnostic code is activated, verify that there are no active CID 1144 diagnostic codes. This code is related to problems with the "Swing Left" Solenoid. An active diagnostic code for the solenoid must be cleared before beginning this procedure.

Note: 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, that all connections are secure, and that all connections 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.

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.

Test Step 1. CHECK THE SENSOR POWER SUPPLY

1. Turn the key start switch and the disconnect switch to the ON position.

2. Disconnect the machine harness connector from the sensor.

3. At the machine harness connector for the sensor, measure the supply voltage between the contact of the power supply, pin 1 (wireJ850-WH(White)) and the ground, pin 2 (wire 993-BR(Brown)).

Expected Result:

The measurement of the supply voltage is 8.0 ± 0.3 VDC.

Results:

• OK - The voltage measurement is approximately 8.0 ± 0.3 VDC. The power supply for the sensor is correct. Proceed to Test Step 2.

• NOT OK - The voltage measurement is less than 8.0 ± 0.3 VDC. The power supply for the sensor is not correct.

  Repair: Either the return circuit 993-BR(Brown)or the supply circuit J850-WH(White)has a bad connection or an open in the machine harness. Examine all the connectors that are in the circuit. Ensure that the connections are clean, that the connections are secure, and that the connections are in good condition.Refer to the CID 0041 diagnostic code procedures in this manual for troubleshooting of the power supply. Correct the problem with the ECM power supply. After the power supply is correct, verify that this diagnostic code is still active before proceeding with this procedure.

  STOP

Test Step 2. CHECK FOR AN OPEN IN THE SENSOR CIRCUIT

The machine harness connector remains disconnected from the sensor.

1. Turn the key start switch and the disconnect switch to the OFF position.

2. At the machine harness connector for the sensor, place a jumper wire between the return contact of the sensor, pin 2 (wire993-BR(Brown)) and the signal contact, pin 3 (wire M818-YL(Yellow)) .

3. Disconnect machine harness connectors from the Cat Grade Control ECM.

4. At the harness connectors for the ECM, measure the resistance from return contact, pin CN1-6 (wire 993-BR(Brown)) to signal contact, pin CN4-6 (wire M818-YL(Yellow)).

Expected Result:

The resistance measurement is less than 5 ohms.

Results:

• OK - The resistance measurement is less than 5 ohms. The sensor circuit is not open. Proceed to Test Step 3.

• NOT OK - The resistance measurement is greater than 5 ohms. There is an open connection or a bad connection in the signal circuit.

  Repair: A resistance measurement greater than 5000 ohms could indicate a wire that is not connected or a wire that is open. A resistance between 5 ohms and 5000 ohms indicates a point in the circuit that is not an open connection. However the connection is not a good connection.Refer to the complete Electrical System Schematic of the machine. Check all the connectors that are in the sensor signal circuit. Ensure that all connections are clean, that all connections are secure, and that all connections are in good condition. Repair the machine harness or replace the machine harness.

  STOP

Test Step 3. CHECK THE SIGNAL CIRCUIT OF THE SENSOR FOR A SHORT

The sensor remains disconnected from the machine harness. The disconnect switch and the key start switch remain in the OFF position. The machine harness connectors remain disconnected from the Cat Grade Control ECM.

1. Remove the jumper wire that was used in the last test step.

2. At the harness connector CN4 for the ECM, measure the resistance from signal contact, pin CN4-6 (wire M818-YL(Yellow)) to all the other contacts that are used for the connectors on the Cat Grade Control ECM.

Expected Result:

Each resistance measurement is greater than 5000 ohms.

Results:

• OK - Each resistance measurement is greater than 5000 ohms. The signal circuit is not shorted to another circuit in the machine harness. Proceed to Test Step 4.

• NOT OK - One or more of the resistance measurements are less than 5000 ohms. There is a short in the machine harness.

  Repair: The signal wire of the sensor M818-YL(Yellow)is shorted to the circuit with the low-resistance measurement in the machine harness.Refer to the complete Electrical System Schematic of the machine. Examine all the connectors in the circuits for points in the machine harness that indicate damage. A damaged point is the most likely location for a short circuit.For information on testing for short circuits and finding short circuits, refer to Testing and Adjusting, "Wiring Harness (Short Circuit) - Test". Repair the machine harness or replace the machine harness.

  STOP

Test Step 4. CHECK THE SIGNAL AT THE SENSOR

The key start switch and the disconnect switch remain in the OFF position.

1. Reconnect the machine harness connectors to the sensor and to the Cat Grade Control ECM.

2. At the machine harness for the sensor connector, use a 151-6320 Removal Tool to remove the signal wire M818-YL(Yellow)and the socket at contact, pin 3, from the harness connector. The machine harness connector remains connected to the pressure sensor .

3. At the back of the sensor connector, insert 7X-1710 Multimeter Probes along the sensor signal contact, pin 3, and the return contact, pin 2.

4. Turn the disconnect switch and the key start switch to the ON position.

5. Measure the voltage of the sensor at the connector contacts pin 2 and pin 3.

Expected Result:

The voltage of the sensor signal is in the range of 0.0 VDC to 8 VDC.

Results:

• OK - The voltage of the sensor signal is in the range of 0.0 VDC to 8 VDC. The sensor signal voltage is in the correct range. Proceed to Test Step 5.

• NOT OK - The voltage of the sensor signal is not in the range of 0.0 VDC to 8 VDC. The sensor may have failed.

  Repair: Verify that the sensor signal is not in the correct voltage range. Start the engine. Run the engine at low idle and check the sensor signal again. If the sensor signal is not in the correct voltage range, the sensor has failed.Replace the pressure sensor for the rod end of the boom cylinder. After replacement of the sensor, verify that the operation of the new sensor is correct before operating the machine.

  STOP

Test Step 5. CHECK THE STATUS OF THE DIAGNOSTIC CODE

1. Inspect the harness connectors. Clean the contacts of the harness connectors. Check the wires for damage to the insulation that is caused by excessive heat, battery acid, or chafing.

2. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the sensor circuit.

3. Reconnect all harness connectors. Make sure that the connectors are fully seated. Observe that the clips for each connector are fastened securely.

4. Turn the disconnect switch and the key start switch to the ON position.

5. Operate the machine.

6. Determine if the CID 5226 FMI 03 diagnostic code is active.

Expected Result:

The CID 5226 FMI 03 diagnostic code is not active.

Results:

• OK - The CID 5226 FMI 03 diagnostic code is not active. The problem has been corrected.

  Repair: The initial diagnostic code was probably caused by a poor electrical connection. The diagnostic code could also be caused by a short at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.

  STOP

• NOT OK - The CID 5226 FMI 03 diagnostic code is still active. The problem has not been corrected.

  Repair: Perform this test step again. If the problem is not corrected, use the Cat^® Electronic Technician service tool to perform a “wiggle test” on the wiring harness. The “wiggle test” can also be used to detect open connections in the machine wiring harness.If a problem is not found in the machine harness, the ECM may have failed.Prior to replacing an ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may greatly reduce repair time. If the cause of the diagnostic code is not found, replace the ECM that has activated the diagnostic code. Refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP