CB44B, CB54B, CD44B and CD54B Vibratory Asphalt Compactors Machine Electronic Control System Caterpillar

Illustration 1	g03746482
Schematic of the Front Drum Eccentric Weight Cylinder Position Sensor

This diagnostic code is recorded when the Machine ECM 1 determines that the signal for the sensor has an open circuit. This sensor is a PWM sensor. The signal wire for the sensor connects to connector contact J-C50-10 (wire M401-GY(Grey)) of the ECM.

Note: Diagnostic Codes for components of the AAC I/O Controller are relayed to the Machine ECM via the CAN Data Link.

The possible causes of this diagnostic code are listed:

• A shorted harness

• A failed sensor

• A short to +Battery

• The Machine ECM 1 has failed. Failure of the ECM is unlikely.

Note: Ensure that the diagnostic code is active and that the diagnostic code indicator is active.

Note: The following procedure can create numerous related diagnostic codes. Reconnect all harnesses. Then, the related diagnostic codes will be shown as being NOT active. Complete the following procedure. Then, clear all of the related diagnostic codes.

System Response:

A Level 2 warning is generated.

Test Step 1. CHECK FOR POWER AT THE SENSOR.

1. Do not disconnect the harness connector from the sensor.

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

3. At the harness connector for the sensor, measure the voltage from contact A (wire 163-WH(White)) to contact C (wire 200-BK(Black)). Use the 7X-1710 Multimeter Probes.

Expected Result:

The voltage is battery voltage.

Results:

• OK - The voltage is battery voltage. Proceed to Test Step 2.

• NOT OK - The voltage is not battery voltage. The circuit is open or grounded.

  Repair: Replace the machine harness or repair the machine harness.

  STOP

Test Step 2. CHECK FOR PROPER GROUND AT THE SENSOR.

Note: Check the “jumper harness” at the sensor for continuity and shorts.

1. The harness remains connected to the sensor.

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

3. At the harness connector for the sensor, measure the resistance from contact C (wire 200-BK(Black)) to frame ground. Use the 7X-1710 Multimeter Probe.

Expected Result:

The resistance is less than 5 ohms.

Results:

• OK - The resistance is less than 5 ohms. The ground circuit is correct. Proceed to Test Step 3.

• NOT OK - The resistance is greater than 5 ohms. The ground circuit in the harness has failed.

  Repair: Replace the harness or repair the harness.

  STOP

Test Step 3. CHECK THE WIRING HARNESS OF THE POSITION SENSOR FOR AN OPEN CIRCUIT.

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

2. Disconnect the harness from the position sensor.

3. At the harness connector for the sensor, connect a jumper wire between contact B (wire M401-GY(Grey)) and contact C (wire 200-BK(Black)) .

4. Disconnect harness connectors from the ECM.

5. At the harness connector for the ECM, measure the resistance between contact J-C50-10 (wire M401-GY(Grey)) and contact J-C50-1 (wire 200-BK(Black)).

Expected Result:

The resistance measurement is less than 5 ohms.

Results:

• YES - The resistance measurement is less than 5 ohms. Proceed to Test Step 4.

• NO - The resistance is greater than 5 ohms. There is an open circuit in the harness.

  Repair: There is an open circuit in the harness. Repair the harness or replace the harness.

  STOP

Test Step 4. CHECK THE WIRING HARNESS OF THE POSITION SENSOR FOR A SHORT TO THE +BATTERY CIRCUIT.

1. The key start switch remains in the OFF position.

2. The machine harness remains disconnected from the position sensor. Remove the jumper wire that was installed in the previous step.

3. The harness connectors remain disconnected from the ECM.

4. At the harness connector for the ECM, measure the resistance between contact J-C50-10 (wire M401-GY(Grey)) of the machine harness to all possible sources of +battery.

Expected Result:

Each resistance measurement should be greater than 5000 ohms.

Results:

• OK - Each resistance measurement is greater than 5000 ohms. The harness is correct. Proceed to Test Step 5.

• NOT OK - One or more resistance measurements are not correct. There is a short in the harness. The short is between signal contact J-C50-10 (wire M401-GY(Grey)) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.

  STOP

Test Step 5. CHECK THE OUTPUT OF THE SENSOR

1. Connect the machine harness connector to the ECM. Connect the harness connector to the sensor.

2. At the harness connector for the sensor, connect the positive lead from the multimeter to contact B (wire M401-GY(Grey)). Use the 7X-1710 Multimeter Probe.

3. At the harness connector for the sensor, connect the negative lead from the multimeter to contact C (wire 200-BK(Black)). Use the 7X-1710 Multimeter Probe.

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

5. Set the multimeter to the setting for frequency (Hz). Measure the output of the sensor.

Expected Result:

The pulse width modulation (PWM) is a signal of 500 Hz between 5% and 95%.

Results:

• OK - The PWM signal from the sensor is a 500 Hz signal between 5% and 95%. Proceed to Test Step 6.

• NOT OK - The PWM signal from the sensor is not a 500 Hz signal or the signal is not between 5% and 95%.

  Repair: The sensor has failed. Replace the sensor.

  STOP

Test Step 6. CHECK IF THE DIAGNOSTIC CODE REMAINS

1. Inspect the contacts of the harness connectors and clean the contacts.

2. Reconnect all harness connectors.

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

4. Operate the machine.

5. Check the status of the CID 4580 FMI 03.

Expected Result:

The CID 4580 FMI 03 is not active.

Results:

• YES - The CID 4580 FMI 03 is not active. The diagnostic code does not exist at this time. 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

• NO - The CID 4580 FMI 03 is active. The diagnostic code has not been corrected. The ECM may have failed.

  Repair: Failure of the ECM is unlikely. 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. If the ECM requires replacement, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP