D6N Track-Type Tractor Caterpillar

Illustration 1	g01737453
Connections of the 10 VDC supply

Illustration 2	g02722153
Location of the machine ECM

This diagnostic code is associated with the 10 VDC supply.

This diagnostic code is recorded when the ECM detects the voltage of the 10 VDC supply 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. An ECM failure is unlikely.

Poor connections can often be the cause of a problem in an electrical circuit. Verify that all of the connections in the circuit are clean and secure. 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 1482 FMI 04 is active before performing this procedure.

System Response:

All of the sensors that receive power from the 10 VDC supply will be 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 to remove the supply wire and the socket. Remove the wires at contact J1-69 (wire 709-OR) and contact J1-56 (wire J765-BU) from the connector. The machine harness connector J1 remains connected to the ECM.

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

4. Use the multimeter probes in order to make contact on the connector pins at the ECM. Measure the voltage at the ECM pins between contact J1-69 and contact J1-56.

Expected Result:

The voltage measurement is 10.0 ± 0.4 VDC.

Results:

• OK - The voltage measurement is 10.0 ± 0.4 VDC. 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 10.0 ± 0.4 VDC. The ECM power supply is not correct.

  Repair: Prior to replacing an ECM, always contact your dealerships 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 keyswitch and the disconnect switch to the ON position.

2. One at a time, disconnect the sensors from the machine harness.

3. After disconnecting each sensor, check the status of the diagnostic code.

Expected Result:

The diagnostic code is no longer active.

Results:

• OK - The diagnostic code is not active when one of the sensors is disconnected. The harness circuit is correct. The sensor that was disconnected has failed.

  Repair: Replace the sensor. Verify that the new sensor has corrected the problem.

  STOP

• NOT OK - The 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

1. The sensors remain disconnected from the machine harness.

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

3. At the machine harness connector for the sensors, measure the voltage between contact 1 (wire 709-OR) and contact 2 (wire J765-BU).

Expected Result:

The voltage measurement is 10.0 ± 0.4 VDC.

Results:

• OK - The voltage measurement is 10.0 ± 0.4 VDC. The voltage is correct. Proceed to Test Step 5.

• NOT OK - The voltage measurement is less than 10.0 ± 0.4 VDC. The measurement is not correct. Proceed to Test Step 4.

Test Step 4. CHECK FOR A SHORT TO GROUND

1. Turn the keyswitch 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 contact J1-69 (wire 709-OR) and frame ground. Measure the resistance between contact J1-56 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 wire 709-OR is shorted in the machine harness to the circuit with the low resistance measurement. Refer to the electrical schematic. Check all of the harness connectors that are in the circuit. Ensure that the connectors are clean and secure. Examine all of the connectors in the circuits. The machine harness may have circuits that are 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 IF THE DIAGNOSTIC CODE REMAINS.

1. Inspect the harness connectors. Clean the contacts of the harness connectors and 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 in order to make sure that the connectors are fully seated. Also, make sure that the clips for each connector are fastened.

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

5. Operate the machine.

6. Check the status of the diagnostic code.

Expected Result:

The diagnostic code is active.

Results:

• YES - The diagnostic code is active. The diagnostic code has not been corrected.

  Repair: Check the circuit again. An ECM failure 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 Troubleshooting, "Electronic Control Module (ECM) - Replace".

  STOP

• NO - The diagnostic code is not active. The initial diagnostic code was probably caused by a poor electrical connection at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.STOP