320E and 323E Excavators Machine Electronic Control System MID 299, 5226-4 Caterpillar

Conditions Which Generate This Code:

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

This diagnostic code is recorded when the ECM reads the voltage of the circuit for the "Swing Left Pilot Pressure" Sensor as being below normal. The signal circuit of the sensor may be shorted to ground.

The possible causes of this diagnostic code are listed below:

• The signal circuit for the sensor is shorted to ground.

• The sensor has failed.

• The Machine ECM has failed. An 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 original diagnostic code has been corrected.

Note: Ensure that the diagnostic code of CID 5226 FMI 04 is active before performing this procedure.

Test Step 1. CHECK THE SENSOR.

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

2. Ensure that the diagnostic code is active.

3. Observe the status of the diagnostic code. Disconnect the sensor from the machine harness.

Expected Result:

The CID 5226 FMI 04 diagnostic code remains active.

Results:

• OK - The diagnostic code remains active. The sensor is correct. Proceed to Test Step 2.

• NOT OK - The diagnostic code is no longer active. The sensor has failed.

  Repair: Replace the entire sensor.

  STOP

Test Step 2. CHECK THE WIRING HARNESS OF THE SENSOR FOR A SHORT TO GROUND.

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

2. Disconnect the machine harness from the sensor.

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

4. At the machine harness connector for the ECM, measure the resistance between the signal contact CN4-6 (wire M818-YL(Yellow)) and all sources of ground. Measure the resistance to all contacts that are used in Cat Grade Control ECM harness connectors.

Expected Result:

Each resistance measurement should be greater than 5000 ohms.

Results:

• OK - Each resistance measurement is greater than 5000 ohms. The machine harness is correct. Proceed to Test Step 3.

• NOT OK - One or more resistance measurements are not correct. There is a short in the machine harness. The short is between signal contact CN4-6 (wire M818-YL(Yellow)) and the circuit with the low-resistance measurement. Repair the machine harness or replace the machine harness.

  STOP

Test Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS.

1. Inspect the contacts of the harness connectors. Clean the contacts of the harness connectors.

2. Reconnect all harness connectors.

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

4. Enter the service mode of the Monitoring System and clear all the inactive diagnostic codes.

5. Operate the machine.

6. Check the status of the CID 5226 FMI 04 diagnostic code.

Expected Result:

The CID 5226 FMI 04 diagnostic code is not active.

Results:

• YES - The CID 5226 FMI 04 diagnostic code is not active. The diagnostic code does not exist currently. The initial diagnostic code was probably caused by a poor electrical connection or a short at one of the harness connectors that was reconnected. Resume normal machine operation.

  STOP

• NO - The CID 5226 FMI 04 diagnostic code is active. The diagnostic code has not been corrected. An ECM failure is unlikely.

  Repair: Exit this procedure and perform this procedure again. If the cause of the diagnostic code is not found, replace the ECM. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP