PL61 Pipelayer and D6K Track-Type Tractor Caterpillar

Illustration 1	g01307576
Machine ECM 8 VDC Sensor Power Supply connections

This diagnostic code is associated with the Machine ECM 8 volt sensor power supply. The 8 volt sensor power supply provides power for the Track Speed Sensors.

The CID 0041 FMI 04 diagnostic code is activated when the ECM detects that the voltage of the 8 volt power supply circuit is lower than normal.

The following conditions could cause this diagnostic code:

• A sensor has failed.

• The power supply circuit is shorted to a ground source.

• The ECM has failed. This is unlikely.

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, secure and 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. Clear the diagnostic codes when the problem has been corrected. Verify that the CID 0041 FMI 04 is active before performing this procedure.

System Response:

A level 2 warning will be generated. Any sensor using this is disabled.

Test Step 1. CHECK THE POWER SUPPLY AT THE ECM

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

2. At ECM connector J1, use a 151-6320 Removal Tool or a similar tool to remove the supply wire and socket at contact J1-44 (wire 497-BU) and the return wire and socket at contact J1-45 (wire J766-PU) from the connector. The machine harness connector J1 remains connected to the ECM.

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

4. Use the multimeter probes in order to make contact on the ECM connector pins. Measure the voltage at the ECM pins between the power supply contact J1-44 and the return contact J1-45.

Expected Result:

The voltage measurement is 8.0 ± 0.4 DCV.

Results:

• OK - The voltage measurement is 8.0 ± 0.4 DCV. The voltage is correct. The ECM power supply is correct. Turn the key start switch and the disconnect switch to the OFF position. Install the wires and sockets that were removed from the J1 connector back into the original locations. Proceed to Test Step 2.

• NOT OK - The voltage measurement is greater than 8.0 ± 0.4 DCV. The ECM power supply is not correct.

  Repair: Prior to replacing an ECM, always contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Troubleshooting, "Electronic Control Module (ECM) - Replace".

  STOP

Test Step 2. CHECK THE SENSORS

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

2. One at a time, disconnect the Track Speed Sensors from the machine harness.

3. After disconnecting each sensor, check the status of the CID 0041 FMI 04 diagnostic code.

Expected Result:

The CID 0041 FMI 04 diagnostic code is no longer active.

Results:

• OK - The CID 0041 FMI 04 diagnostic code is not active when the sensor is disconnected. The harness circuit is correct. The sensor that was just disconnected has failed.

  Repair: Replace the sensor.

  STOP

• NOT OK - The CID 0041 FMI 04 diagnostic code is still active. The machine harness may be shorted to a ground source. Proceed to Test Step 3.

Test Step 3. CHECK THE VOLTAGE AT THE SENSORS

The sensors remain disconnected from the machine harness.

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

2. At the machine harness connector for one of the sensors, measure the voltage between supply contact 1 (wire 497-BU) to return contact 2 (wire J766-PU).

Expected Result:

The voltage measurement is 8.0 ± 0.4 DCV.

Results:

• OK - The voltage measurement is 8.0 ± 0.4 DCV. The voltage is correct. Proceed to Test Step 5.

• NOT OK - The voltage measurement is less than 8.0 ± 0.4 DCV. The measurement is not correct. Proceed to Test Step 4.

Test Step 4. CHECK FOR A SHORT TO GROUND

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

2. Disconnect the machine harness connectors J1 and J2 from the Machine ECM.

3. At the harness connector for the ECM, measure the resistance between supply contact J1-44 (wire 497-BU) and frame ground. Measure the resistance between supply contact J1-44 and all of the other contacts that are used in the J1 and J2 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 circuit in the machine harness is correct. Proceed to Test Step 5.

• NOT OK - One or more of the resistance measurements is less than 5000 ohms. The circuit is shorted in the machine harness.

  Repair: The power supply wire 497-BU is shorted in the machine harness to the circuit with the low resistance measurement. Refer to the complete Electrical System Schematic for your machine. Check all harness connectors that are in the power supply circuit. Ensure that the connectors are clean and secure.Refer to the complete machine Electrical System Schematic. Examine all of the connectors in the circuits for points in the machine harness where the circuits could be shorted. For information on testing for short circuits and finding short circuits, refer to Troubleshooting, "Wiring Harness (Short Circuit) - Test". Repair the machine harness or replace the machine harness.

  STOP

Test Step 5. CHECK THE STATUS OF THE DIAGNOSTIC CODE

1. Inspect the harness connectors. Clean the contacts for the harness connectors. Check all wires for damage from chafing, corrosion, or excessive heat.

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 and the clips for each connector are completely fastened.

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

5. Operate the machine.

6. Determine if the CID 0041 FMI 04 diagnostic code is active.

Expected Result:

The CID 0041 FMI 04 diagnostic code is active.

Results:

• YES - The CID 0041 FMI 04 diagnostic code is active. The problem has not been corrected.

  Repair: Check the circuit again.If the cause of the problem is not found, contact the Technical Communicator for your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, see Troubleshooting, "Electronic Control Module (ECM) - Replace".

  STOP

• NO - The CID 0041 FMI 04 diagnostic code is not active. The problem 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