100-200 kW Tactical Quiet Generators (TQG) EMCP2 Plus Caterpillar

This diagnostic code is associated with an electrical system voltage that is below normal. The FMI 04 means that the engine electronic control module (ECM) has determined that the electrical system voltage is below normal.

Illustration 1	g00681915
Simplified System Schematic For Battery Voltage On MUI Engines

Illustration 2	g00689475
System Schematic For Battery Voltages On EUI And PEEC Engines

The EMCP II+ monitors the battery voltage in order to protect the EMCP II+ from a battery problem or from a charging problem. The battery voltage is received from the engine electronic control module (ECM) by the CAT data link. If you receive a CID 168 E diagnostic code, refer to Troubleshooting, " 3500B Generator Set Engines" or Troubleshooting, " 3406E Generator Set Engines". The GSC+ treats a CID 168 FMI 4 as an alarm diagnostic code. The threshold for a CID 168 FMI 04 for battery voltage is less than 18 DCV for 24 volt system. The threshold for a CID 168 FMI 4 for battery voltage is less than 18 DCV for a 32 volt system.

The setpoint for the system voltage (P007) specifies the battery voltage.

24 - 24 Volt System

32 - 32 Volt System

Note: The GSC+ does not receive battery power when the ECS is in the OFF/RESET position. When contact 6 is connected to one of the contacts (8, 9, 10), the GSC+ receives battery power when the ECS is in the OFF/RESET position.

Before beginning this procedure, ensure that the following steps have been performed:

• VERIFY THE DIAGNOSTIC CODE.

• Make sure that the CID 168 FMI 04 is shown on the display.

• Enter service mode.

• Turn the ECS to the STOP position.

• Program setpoint P023 to 0.

• Turn the ECS to the OFF/RESET position.

Note: When Program Setpoint P023 is set to 0, the GSC+ is programmed for an MUI engine. The engine's electronic control module (ECM) is eliminated as a possibility of the problem.

Test Step 1. CHECK THE SYSTEM'S VOLTAGE.

1. Turn the ECS to the STOP.

2. Measure the voltage across the battery terminals.

Expected Result:

For a 24 volt system, the voltage should be between 24.8 DCV and 29.5 DCV. For a 32 volt system, the voltage should be between 33.1 DCV and 39.3 DCV.

Results:

• OK - For a 24 volt system, the voltage is 24.8 DCV to 29.5 DCV. For a 32 volt system, the voltage is 33.1 DCV to 39.3 DCV. Proceed to 2.

• NOT OK - For 24 volt systems, the voltage is not between 24.8 DCV to 29.5 DCV. For a 32 volt system, the voltage is not between 33.1 DCV to 39.3 DCV. The problem is in the charging system.

  Repair: Proceed to Testing and Adjusting, "Charging System - Test".

  STOP

Test Step 2. COMPARE THE VOLTAGE BETWEEN DC CONNECTOR TERMINALS AND THE BATTERY VOLTAGE.

1. Turn the ECS to the STOP position.

2. Measure the battery voltage across the battery terminals. Take note of the battery voltage.

3. Measure the voltage between terminal 1 on the DC connector and terminal 11. Repeat the measurement between terminal 1 and terminal 12. Repeat the measurement between terminal 2 and terminal 11. Repeat the measurement between terminal 2 and terminal 12. Take note of the voltages.

4. Compare the voltage measured at the battery with the voltage measured between the DC connector terminals.

Expected Result:

The voltage measured at the battery and the voltage measured between the DC connector terminals.

Results:

• OK - The voltage measured at the battery and the voltage measured between the DC connector terminals are within 2.0 DCV of each other. Proceed to Test Step 3.

• NOT OK - The voltage measured at the battery and the voltage measured between the DC connector terminals are NOT within 2.0 DCV of each other. The wiring harness is not correct.

  Repair: Repair the wiring harness or replace the wiring harness.

  Proceed to Test Step 10.

Test Step 3. COMPARE THE VOLTAGE BETWEEN THE DC CONNECTOR TERMINALS AND THE ECS.

1. Turn the ECS to the STOP position.

2. Measure the voltage between terminal 1 on the DC connector and terminal 11. Repeat the measurement between terminal 1 and terminal 12. Repeat the measurement between terminal 2 and terminal 11. Repeat the measurement between terminal 2 and terminal 12. Take note of the voltages.

3. Measure the voltage at terminal 6 on the ECS. Take note of the voltage.

4. Compare the voltage that was measured at the DC connector terminals with the voltage that was measured at the ECS.

Expected Result:

The voltage that was measured at the DC connector terminals and the voltage that was measured at the ECS are within 2.0 DCV of each other.

Results:

• OK - The voltage that was measured at V and the voltage that was measured at the ECS are within 2.0 DCV of each other. Proceed to Test Step 4.

• NOT OK - The voltage that was measured at the DC connector terminals and the voltage that was measured at the ECS are NOT within 2.0 DCV of each other. The wiring harness is not correct.

  Repair: Repair the wiring harness or replace the wiring harness.

  Proceed to Test Step 10.

Test Step 4. CHECK THE CONTINUITY OF THE ECS (TERMINAL 7).

1. There is a jumper wire on the ECS that attaches terminal 6 to terminal 9. Remove this wire.

2. Place the ECS in the "OFF/RESET" position.

3. With an ohmmeter, measure the resistance between ECS terminal 6 and ECS terminal 7. Continue to measure the resistance between ECS terminal 6 and ECS terminal 7 while the ECS is rotated to the "AUTO", "MANUAL", and "STOP" positions. Take note of the readings.

Expected Result:

When the ECS is in the OFF/RESET position, there should be less than 5 Ohms resistance between ECS Terminal 7 and ECS Terminal 6. There should be greater than 5000 Ohms between ECS Terminal 7 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions.

Results:

• OK - There are less than 5 Ohms resistance between ECS Terminal 7 and ECS Terminal 6 when the ECS is in the OFF/RESET position. There are greater than 5000 Ohms between ECS Terminal 7 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions. The ECS has not failed. Proceed to Test Step 8.

• NOT OK - There are more than 5 Ohms resistance between ECS Terminal 7 and ECS Terminal 6 when the ECS is in the OFF/RESET position. There are less than 5000 Ohms between ECS Terminal 7 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions. The ECS has failed. Proceed to Test Step 10.

Test Step 5. CHECK THE CONTINUITY OF THE ECS (TERMINAL 8).

1. There is a jumper wire on the ECS that attaches terminal 6 to terminal 9. Remove this wire.

Expected Result:

There should be less than 5 Ohms resistance between ECS Terminal 8 and ECS Terminal 6 when the ECS is in the OFF/RESET position. There should be greater than 5000 Ohms between ECS Terminal 8 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions.

Results:

• OK - There are less than 5 Ohms resistance between ECS Terminal 8 and ECS Terminal 6 when the ECS is in the OFF/RESET position. There are greater than 5000 Ohms between ECS Terminal 8 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions. The ECS has not failed. Proceed to Test Step 8.

• NOT OK - There are more than 5 Ohms resistance between ECS Terminal 8 and ECS Terminal 6 when the ECS is in the OFF/RESET position. There are less than 5000 Ohms between ECS Terminal 8 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions. The ECS has failed.

  Repair: Replace the ECS. Reinstall the jumper wire.

  Proceed to Test Step 10.

Test Step 6. CHECK THE CONTINUITY OF THE ECS (TERMINAL 9).

1. There is a jumper wire on the ECS that attaches terminal 6 to terminal 9. Remove this wire.

2. Return the ECS to the "OFF/RESET" position.

3. With an ohmmeter, measure the resistance between ECS terminal 9 and ECS terminal 6. Continue to measure the resistance between ECS terminal 9 and ECS terminal 6 while the ECS is rotated to the "AUTO", "MANUAL", and "STOP" positions. Take note of the readings.

Expected Result:

There should be less than 5 Ohms resistance between ECS Terminal 9 and ECS Terminal 6 when the ECS is in the OFF/RESET position. There should be greater than 5000 Ohms between ECS Terminal 9 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions.

Results:

• OK - There are less than 5 Ohms resistance between ECS Terminal 9 and ECS Terminal 6 when the ECS is in the OFF/RESET position. There are greater than 5000 Ohms between ECS Terminal 9 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions. The ECS has not failed. Proceed to Test Step 8.

• NOT OK - There are more than 5 Ohms resistance between ECS Terminal 9 and ECS Terminal 6 when the ECS is in the OFF/RESET position. There are less than 5000 Ohms between ECS Terminal 9 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions. The ECS has failed.

  Repair: Replace the ECS. Reinstall the jumper wire.

  Proceed to Test Step 10.

Test Step 7. CHECK THE CONTINUITY OF THE ECS (TERMINAL 10).

1. There is a jumper wire on the ECS that attaches terminal 6 to terminal 9. Remove this wire.

2. Return the ECS to the "OFF/RESET" position.

3. With an ohmmeter, measure the resistance between ECS terminal 10 and ECS terminal 6. Continue to measure the resistance between ECS terminal 10 and ECS terminal 6 while the ECS is rotated to the "AUTO", "MANUAL", and "STOP" positions. Take note of the readings.

Expected Result:

There should be less than 5 Ohms resistance between ECS Terminal 10 and ECS Terminal 6 when the ECS is in the OFF/RESET position. There should be greater than 5000 Ohms between ECS Terminal 10 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions.

Results:

• OK - There are less than 5 Ohms resistance between ECS Terminal 10 and ECS Terminal 6 when the ECS is in the OFF/RESET position. There are greater than 5000 Ohms between ECS Terminal 10 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions. The ECS has not failed. Proceed to Test Step 8.

• NOT OK - There are more than 5 Ohms resistance between ECS Terminal 10 and ECS Terminal 6 when the ECS is in the OFF/RESET position. There are less than 5000 Ohms between ECS Terminal 10 and ECS Terminal 6 when the ECS is in the AUTO, MANUAL, or STOP positions. The ECS has failed. Proceed to Test Step 10.

Test Step 8. COMPARE THE VOLTAGE BETWEEN RM-1 AND THE ECS.

1. Turn the ECS to the STOP position.

2. Check the voltage between "RM-1" and "RM-28". Take note of the voltage.

3. Check the voltage on ECS contact 10. Take note of the voltage.

4. Compare the following voltage measurements: the voltage measured between "RM-1" and "RM-28" and the voltage measured on ECS contact 10.

Expected Result:

The voltage that was measured between "RM-1" and "RM-28" should be within 2 DCV of the voltage that was measured on ECS contact 10.

Results:

• OK - The voltage that was measured between "RM-1" and "RM-28" is within 2 DCV of the voltage that was measured on ECS contact 10. The harness is correct. Proceed to Test Step 9.

• NOT OK - The voltage that was measured between "RM-1" and "RM-28" is NOT within 2 DCV of the voltage that was measured on ECS contact 10. Proceed to Test Step 10.

Test Step 9. COMPARE THE VOLTAGE BETWEEN RM-1 AND THE LOWER DISPLAY.

1. Turn the ECS to the STOP position.

2. Check the voltage between "RM-1" and "RM-28". Take note of the voltage.

3. Check the voltage that is shown on the lower display. Take note of the voltage.

4. Compare the following voltage measurements: the voltage measured between "RM-1" and "RM-28" and the voltage measured on the lower display.

Expected Result:

The voltage that was measured between "RM-1" and "RM-28" should be within 2 DCV of the voltage that was measured on the lower display.

Results:

• OK - The voltage that was measured between "RM-1" and "RM-28" is within 2 DCV of the voltage that was measured on the lower display.

  Repair: The problem is probably an intermittent failure that was caused by a failed connector. Inspect the electrical connectors. Refer to Testing and Adjusting, "Electrical Connector - Inspect". If the failed connector can not be found, the GSC+ may have failed. It is unlikely that the GSC+ has failed. Exit this procedure and perform this entire procedure again. If the problem remains, replace the GSC+. See Testing And Adjusting, "EMCP Electronic Control (Generator Set) - Replace".

  STOP

• NOT OK - The voltage that was measured between "RM-1" and "RM-28" is NOT within 2 DCV of the voltage that was measured on the lower display. The GSC+ has failed.

  Repair: The GSC+ may have failed. It is unlikely that the GSC+ has failed. Exit this procedure and perform this entire procedure again. If the problem remains, replace the GSC+. See Testing And Adjusting, "EMCP Electronic Control (Generator Set) - Replace".

  STOP

Test Step 10. REPROGRAM THE GSC+.

1. Turn the ECS to the STOP position.

2. Program the setpoint P023. Refer to System Operation, "Engine Generator Programming OP5-0".

3. Turn the ECS to the OFF/RESET position. If applicable, disconnect the jumper wire on the ECS that is between pin 6 and pin 9. Not all generators will have a jumper wire between pin 6 and pin 9.

4. Verify that the diagnostic code is no longer present.

5. Replace the jumper between pin 6 and pin 9. Not all generators will have a jumper wire between pin 6 and pin 9.

Expected Result:

Setpoint P023 should be programmed to the correct setting. The diagnostic code should no longer be present.

Results:

• OK - Setpoint P023 is programmed to the correct setting. The diagnostic code is no longer present.STOP

• NOT OK - Setpoint P023 is not programmed to the correct setting. The diagnostic code is still present.

  Repair: Reprogram the GSC+. Refer to System Operation, "Engine Generator Programming OP5-0".

  STOP