C7 and C9 On-Highway Engines Caterpillar

The ECM monitors the current flow through the circuit for the ARD purge air actuator. The ECM logs a diagnostic trouble code if the current flow through the circuit is incorrect. Table 1 lists the diagnostic codes for incorrect current flow. Codes can be observed using Caterpillar Electronic Technician (ET).

Note: The codes in table 1 are never active.

Illustration 1	g01444828
Schematic diagram

Test Step 1. Inspect the Wiring and the Electrical Connections

1. Verify that the engine is off.

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Illustration 2	g01444843
Typical left side view (1) Coil for the ARD purge air actuator

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Illustration 3	g01773753
(1) The coil for the ARD purge air actuator can be serviced separately.

2. Check the wiring between coil (1) and the P2 connector. Visually inspect the electrical components. Look for the following problems:
   • Loose connections or damaged connectors

   • Moisture on the connectors or the wiring

   • Damage that is caused by excessive heat

   • Damage that is caused by chafing

   • Improper routing of wiring

   • Damaged insulation

3. Perform a ten pound pull test on each of the wires at the harness connectors for the coil. This verifies that each wire is crimped to the terminal and that the terminals are fully inserted into the connector.

Expected Result:

There is a problem with the wiring.

Results:

• There is a problem with the wiring. -

  Repair: Repair the wiring problem. Replace parts, if necessary.

  If you are troubleshooting a -5 code proceed to Test Step 2. If you are troubleshooting a -6 code proceed to Test Step 3.

• The wiring appears to be OK. - If you are troubleshooting a -5 code proceed to Test Step 2. If you are troubleshooting a -6 code proceed to Test Step 3.

Test Step 2. Test for a Open in the Circuit for the ARD Purge Air Actuator.

Note: The "ARD Fuel Nozzle Cleaner Configuration" parameter must be programmed to "Air Purge" in order for this procedure to work correctly.

Note: You must perform all of the steps in the following procedure in order to properly test for a 3490-5 code.

1. Turn the keyswitch to the OFF position and wait until Cat ET is disconnected.

2. Turn the keyswitch to the ON position and wait until Cat ET is connected.

3. Check for a logged 3490-5 code. If there is a logged 3490-5 clear the code.

4. Select the following menus in order to view the overrides:
   • Diagnostics

   • Diagnostic Tests

   • System Troubleshooting Settings

5. Verify that the "ARD Purge Air Actuator Override" is disabled. The disabled condition is indicated by a dash "-" in the "value" field for the override.

6. View all logged codes.

7. Disconnect the electrical connector for the ARD purge air actuator.

8. Wait for five seconds.

9. Connect the electrical connector for the ARD purge air actuator.

10. Wait for five seconds.

Expected Result:

There is one occurrence of a logged 3490-5 code.

Results:

• A 3490-5 was logged. - The presence of a logged 3490-5 code indicates that the ECM detected the open circuit and that the circuit no longer has a fault. Return the engine to service.STOP

• A 3490-5 was not logged. - The absence of a logged 3490-5 code indicates that there is an open circuit. Make the necessary repairs. Then, test for an open circuit again by using the above procedure. You must perform all of the steps in the above procedure in order to properly test for a 3490-5 code.

Test Step 3. Test for a Short in the Circuit for the ARD Purge Air Actuator.

Note: The "ARD Fuel Nozzle Cleaner Configuration" parameter must be programmed to "Air Purge" in order for this procedure to work correctly.

Note: You must perform all of the steps in the following procedure in order to properly test for a 3490-6 code.

1. Turn the keyswitch to the OFF position and wait until Cat ET is disconnected.

2. Turn the keyswitch to the ON position and wait until Cat ET is connected.

3. Check for a logged 3490-6 code. If there is a logged 3490-6 clear the code.

4. Select the following menus in order to view the overrides:
   • Diagnostics

   • Diagnostic Tests

   • System Troubleshooting Settings

5. Verify that the "ARD Purge Air Actuator Override" is off. The off condition is indicated by the word "OFF" in the "value" field for the override.

6. View all logged codes.

7. Disconnect the electrical connector for the ARD purge air actuator.

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Illustration 4	g01773796
Recommended method of creating a short for the harness connector

8. Create a short circuit between the two terminals of the engine harness connector for the ARD purge air actuator.

9. Wait for five seconds.

10. Remove the short circuit between the two terminals of the engine harness connector for the ARD purge air actuator.

11. Connect the electrical connector for the ARD purge air actuator.

12. Wait for five seconds.

Expected Result:

There is one occurrence of a logged 3490-6 code.

Results:

• A 3490-6 was logged. - The presence of a logged 3490-6 code indicates that the ECM detected the short circuit and that the circuit no longer has a fault. Return the engine to service.STOP

• A 3490-6 was not logged. - The absence of a logged 3490-6 code indicates that there is a short circuit. Make the necessary repairs. Then, test for a short circuit again by using the above procedure. You must perform all of the steps in the above procedure in order to properly test for a 3490-6 code.STOP