CB54 and CB64 Asphalt Compactors Machine Electronic Control System Caterpillar

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Schematic of the Main Pump Swash Plate Angle Sensor

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General Area Location for the Main Pump Swash Plate Angle Sensor (RH Side)

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Main Swash Plate Angle Sensor (View from below the machine)

Note: The sensor is best accessed from below the machine. If equipped, the optional cover plate (belly guard) will need to be removed.

This diagnostic code is associated with the Main Pump Swash Plate Angle Sensor. The FMI 04 means that the ECM has determined that the voltage of the circuit for the position sensor is below normal.

The input voltage of 0.25 DCV to 4.75 DCV from the sensor corresponds to a swashplate angle of −45 degrees to 45 degrees. The machine ECM recognizes a valid swashplate angle in the range of −40 degrees to 40 degrees. If the angle is less than −40 degrees, the ECM determines that the value is below the normal operational range. If the angle is greater than 40 degrees, the ECM determines that the value is above the normal operational range.

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 ECM has failed. This 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. Ensure that the diagnostic code of CID 1618 FMI 04 is active before performing this procedure.

Note: Use the 146-4080 Digital Multimeter for the measurements in this procedure.

System Response:

The machine will transition to low speed mode (“turtle”). Low speed mode will be maintained until the fault is cleared.

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 1618 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 2.

• NOT OK - The diagnostic code is no longer active.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

  Repair: Replace the 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 the J1 machine harness connector from the ECM.

4. At the machine harness connector for the ECM, measure the resistance from the signal contact J1-36 (wire N790-PU(Purple)) of the machine harness to all possible sources of ground. Measure the resistance to all contacts of the machine harness connectors for the ECM.

Expected Result:

Each resistance measurement is 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 is not correct. There is a short in the machine harness.

  Repair: The short is between signal contact J1-36 (wire N790-PU(Purple)) 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 harness connectors. Clean the contacts of the harness connectors. Check the wires for damage to the insulation that is caused by excessive heat, corrosion, or chafing.

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

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

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

5. Use the Caterpillar Electronic Technician (ET) service tool, if available, in order to perform a “Wiggle Test” on the machine wiring harness. The wiggle test can detect intermittent shorts or opens in the machine wiring harness.

6. Operate the machine.

7. Determine if the CID 1618 FMI 04 diagnostic code is active.

Expected Result:

The CID 1618 FMI 04 is active.

Results:

• YES - The CID 1618 FMI 04 is active. The diagnostic code has not been corrected. The ECM may have failed.

  Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. Prior to replacing an ECM, always contact your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP

• NO - The CID 1618 FMI 04 is not active. The diagnostic code does not exist at this time.

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

  STOP