G3516B Engines Caterpillar

The Electronic Control Module (ECM) controls the throttle actuator by adjusting current flow through the actuator's solenoid.

The 1440-05 diagnostic code is probably caused by a problem with an electrical connector or an open circuit in a harness. Under certain circumstances, the 1440-05 diagnostic code can occur if the low side wire is shorted to ground. The next likely cause is an open circuit inside the actuator solenoid. The least likely cause is a problem with the ECM.

The 1440-06 diagnostic code is probably caused by a short circuit in a harness or a problem with an electrical connector. The next likely cause is a short circuit inside the actuator solenoid. The least likely cause is a problem with the ECM.

Illustration 1	g01075602
Schematic of the circuit for the throttle actuator

Test Step 1. Inspect the Electrical Connectors and Wiring

Note: This Test Step is important for troubleshooting a problem with instability.

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Illustration 2	g01075604
Terminal box (1) J2/P2 connectors for the ECM (2) 16 amp circuit breaker (3) J10/P10 connectors for the harness from the throttle actuator

1. Set the engine control to the OFF/RESET mode. Switch 16 amp circuit breaker (2) to the OFF position.

   Note: For the following steps, refer to Troubleshooting, "Inspecting Electrical Connectors".

2. Thoroughly inspect the following connectors:

   • J2/P2 connectors

   • J10/P10 connectors on the terminal box

   1. Check the torque of the allen head screw for the ECM connector. The proper torque is 6 ± 1 N·m (55 ± 9 lb in).
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      Illustration 3	g01075606
      Harness side of the P2 connector (P2-63) High side wire for the throttle actuator (P2-64) Low side wire for the throttle actuator

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      Illustration 4	g00895202
      Harness side of the P10 connector (P10-C) High side wire for the throttle actuator (P10-D) Low side wire for the throttle actuator

   2. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit for the throttle actuator.
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      Illustration 5	g01075607
      Throttle actuator (4) Throttle actuator (5) Connectors for the throttle actuator

   3. Thoroughly inspect the connectors for the throttle actuator for moisture and for contamination. Check the harness and wiring for abrasion and for pinch points from the throttle actuator to the ECM.

Expected Result:

All of the connectors and terminals are connected properly. The connectors and the wiring do not have corrosion, abrasion, or pinch points.

Results:

• OK - The components are in good condition with proper connections. If you are troubleshooting a 1440-05 diagnostic code, proceed to Test Step 2. If you are troubleshooting a 1440-06 diagnostic code, proceed to Test Step 8.

• Not OK - The components are not in good condition and/or at least one connection is improper.

  Repair: Perform the necessary repairs and/or replace parts, if necessary.

  STOP

Test Step 2. Check the Solenoid and Harnesses for an Open Circuit

1. Set the engine control to the OFF/RESET mode. Switch the 16 amp circuit breaker OFF.

2. Disconnect the P2 connector.

3. Measure the resistance between terminals P2-63 and P2-64. During this measurement, wiggle the harnesses in order to check for an intermittent problem with the harness. Be sure to wiggle the harnesses near each of the connectors.

Expected Result:

The resistance is between 5.0 and 20.6 Ohms.

Results:

• OK - The resistance is between 5.0 and 20.6 Ohms. The solenoid and wiring appear to be OK. The low side wire may have a short to ground, or the ECM may have a problem. Proceed to Test Step 3.

• Not OK - The resistance is higher than 20.6 Ohms. There is a problem with a connector and/or with the wiring for the solenoid, or the solenoid may have a problem. Proceed to Test Step 6.

Test Step 3. Check All of the Low Side Wiring for a Short to Ground

1. Verify that the P2 connector is disconnected from the ECM.

2. Measure the resistance between the ground strap for the ECM and P2-64. During this measurement, wiggle the harnesses in order to check for an intermittent problem with the harness. Be sure to wiggle the harnesses near each of the connectors.

Expected Result:

The resistance is greater than 20,000 Ohms.

Results:

• OK - The resistance measurement is greater than 20,000 Ohms. The low side wire for the throttle actuator appears to be OK. Proceed to Test Step 12.

• Not OK - The resistance measurement is less than 20,000 Ohms. There is a problem with the low side wire for the throttle actuator. Proceed to Test Step 4.

Test Step 4. Check the Low Side Wiring inside the Engine Harness for a Short to Ground

1. Disconnect the P10 connector from the terminal box.

2. Measure the resistance between the ground strap for the ECM and terminal P10-D. During this measurement, wiggle the engine harness in order to check for an intermittent problem with the harness. Be sure to wiggle the harness near each of the connectors.

Expected Result:

The resistance is greater than 20,000 Ohms.

Results:

• OK - The resistance is greater than 20,000 ohms. The low side wire inside the engine harness appears to be OK. The low side wire inside the terminal box may have a problem. There may be a problem with a connector.

  Repair: Repair the harness and/or the connector, when possible. Replace parts, if necessary.

  STOP

• Not OK - The resistance is less than 20,000 Ohms. The low side wire inside the engine harness may have a problem, or there may be a problem with the solenoid. Proceed to Test Step 5.

Test Step 5. Check the Solenoid for an Internal Short Circuit

1. Disconnect the connector from the throttle actuator.
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   Illustration 6	g00895288
   Throttle actuator (1) Connector's shell (2) Terminal B

2. Measure the resistance between the connector's shell and terminal B.

Expected Result:

The resistance is greater than 20,000 Ohms.

Results:

• OK - The resistance is greater than 20,000 Ohms. The solenoid does not have an internal short circuit. The low side wire inside the engine harness has a short to ground.

  Repair: Repair the engine harness or connectors, when possible. Replace parts, if necessary.

  STOP

• Not OK - The resistance is less than 20,000 Ohms. The solenoid has an internal short circuit.

  Repair: Replace the solenoid. Refer to Operation and Maintenance Manual, "Electrohydraulic Actuator - Recondition".

  STOP

Test Step 6. Check the Engine Harness and the Solenoid for an Open Circuit

1. Disconnect the P10 connector from the terminal box.
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   Illustration 7	g00895298
   Harness connector P10 (P10-C) High side wire for the throttle actuator (P10-D) Low side wire for the throttle actuator

2. Measure the resistance between terminals P10-C and P10-D. During this measurement, wiggle the harnesses in order to check for an intermittent problem with the harness. Be sure to wiggle the harnesses near each of the connectors.

Expected Result:

The resistance is between 5.0 and 20.6 Ohms.

Results:

• OK - The resistance is between 5.0 and 20.6 Ohms. The engine harness and the solenoid appear to be OK. The wiring inside the terminal box or the terminal box's connectors may have a problem.

  Repair: Repair the wiring and/or connectors, when possible. Replace parts, if necessary.

  STOP

• Not OK - The resistance is greater than 20.6 Ohms. There is a problem with the engine harness or the solenoid. Proceed to Test Step 7.

Test Step 7. Check the Solenoid for an Open Circuit

1. Disconnect the connector from the throttle actuator.
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   Illustration 8	g01075628
   Throttle actuator (1) Terminal A (2) Terminal B

2. Measure the resistance between terminals A and B on the throttle actuator's connector.

Expected Result:

The resistance is between 5.0 and 10.3 Ohms.

Results:

• OK - The resistance of the solenoid is between 5.0 and 10.3 Ohms. The solenoid does not have an open circuit. There is an open circuit in the engine harness. There may be a problem with a connector.

  Repair: Repair the engine harness or connectors, when possible. Replace parts, if necessary.

  STOP

• Not OK - The resistance of the solenoid is higher than 10.3 Ohms. The resistance of the solenoid is incorrect. The solenoid has an open circuit.

  Repair: Replace the solenoid. Refer to Operation and Maintenance Manual, "Electrohydraulic Actuator - Recondition".

  STOP

Test Step 8. Check all of the Wiring and the Solenoid for a Short Circuit

1. Disconnect the P2 connector.

2. Measure the resistance between terminals P2-63 and P2-64. During this measurement, wiggle the harnesses in order to check for an intermittent problem with the harness. Be sure to wiggle the harnesses near each of the connectors.

Expected Result:

The resistance is between 5.0 and 20.6 Ohms.

Results:

• OK - The resistance is between 5.0 and 20.6 Ohms. The solenoid and the wiring do not have a short circuit. Proceed to Test Step 11.

• Not OK - The resistance is less than 5.0 Ohms. There is a problem with a connector and/or with the wiring, or the solenoid has a problem. Proceed to Test Step 9.

Test Step 9. Check the Engine Harness and the Solenoid for a Short Circuit

1. Disconnect the P10 connector from the terminal box.

2. Measure the resistance between terminals C and D on the P10 harness connector. During this measurement, wiggle the harnesses in order to check for an intermittent problem with the harness. Be sure to wiggle the harnesses near each of the connectors.

Expected Result:

The resistance is between 5.0 and 20.6 Ohms.

Results:

• OK - The resistance is between 5.0 and 20.6 Ohms. The engine harness and the solenoid appear to be OK. The wiring inside the terminal box has a problem. There may be a problem with a connector.

  Repair: Repair the wiring and/or the connector, when possible. Replace parts, if necessary.

  STOP

• Not OK - The resistance is lower than 5.0 Ohms. There is a problem with the engine harness or with the solenoid. Proceed to Test Step 10.

Test Step 10. Check the Solenoid for a Short Circuit

1. Disconnect the connector from the throttle actuator.
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   Illustration 9	g01075628
   Throttle actuator (1) Terminal A (2) Terminal B

2. Measure the resistance between terminals A and B on the throttle actuator's connector.

Expected Result:

The resistance is between 5.0 and 10.3 Ohms.

Results:

• OK - The resistance of the solenoid is between 5.0 and 10.3 Ohms. The solenoid does not have a problem. The engine harness appears to have a short circuit.

  Repair: Repair the engine harness or connectors, when possible. Replace parts, if necessary.

  STOP

• Not OK - The resistance of the solenoid is lower than 5.0 Ohms. The resistance of the solenoid is incorrect.

  Repair: Replace the solenoid. Refer to Operation and Maintenance Manual, "Electrohydraulic Actuator - Recondition".

  STOP

Test Step 11. Create an Open Circuit and Check the Operation of the ECM

1. Prevent fuel from entering the engine. Verify that the gas supply to the engine is OFF.

2. Verify that the engine control is in the OFF/RESET mode. Verify that the 16 amp circuit breaker is OFF.

3. Use a 151-6320 Wire Removal Tool to remove terminals P2-63 and P2-64. This will create an open circuit.

4. Switch the 16 amp circuit breaker ON.

5. If a 1440-05 diagnostic code and/or a 1440-06 diagnostic code is logged, clear the code.

6. Set the engine control to the START mode and crank the engine. Allow a minimum of 30 seconds for the generation of any codes. Then set the engine control to the STOP mode.

7. Observe the "Active Diagnostic" screen on the Caterpillar Electronic Technician (ET). Look for a 1440-05 diagnostic code.

Expected Result:

A 1440-05 diagnostic code is activated.

Results:

• OK - When an open circuit was created, a 1440-05 diagnostic code was activated. The ECM is operating correctly. The problem appears to be resolved. The initial diagnostic code was probably caused by a poor electrical connection.

  Repair: Perform the following procedure:

  Set the engine control to the OFF/RESET mode. Switch the 16 amp circuit breaker OFF.

  Reinstall the terminals into the P2 connector. Pull on the wires in order to verify proper installation of the terminals.

  Reconnect all of the connectors. Verify that the problem is resolved.

  STOP

• Not OK - When an open circuit was created, a 1440-05 diagnostic code was not activated. The ECM may have a problem.

  Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the problem is not resolved, perform the following procedure:

  Temporarily install a new ECM. Refer to Troubleshooting, "Replacing the ECM".

  If the problem is resolved with a new ECM, install the original ECM and verify that the problem returns. If the new ECM operates correctly and the original ECM does not operate correctly, replace the original ECM. Follow the instructions in Troubleshooting, "Replacing the ECM".

  STOP

Test Step 12. Create a Short Circuit and Check the Operation of the ECM

1. Prevent fuel from entering the engine. Verify that the gas supply to the engine is OFF.

2. Verify that the engine control is in the OFF/RESET mode. Verify that the 16 amp circuit breaker is OFF.

3. Use a 151-6320 Wire Removal Tool to remove terminals P2-63 and P2-64.

4. Fabricate a jumper wire with Deutsch sockets on the ends. Insert one end of the jumper wire into the open terminal 63 of the P2 connector. Verify that the socket is making contact with pin 63 in the J2 connector.

5. Insert the other end of the jumper wire into the open terminal 64 of the P2 connector. Verify that the socket is making contact with pin 64 in the J2 connector. This will replace the wiring for the throttle actuator with a short circuit.

6. Switch the 16 amp circuit breaker ON.

7. If a 1440-05 diagnostic code and/or a 1440-06 diagnostic code is logged, clear the code.

8. Set the engine control to the START mode and crank the engine. Allow a minimum of 30 seconds for the generation of any codes. Then set the engine control to the STOP mode.

9. Observe the "Active Diagnostic" screen on Cat ET. Look for a 1440-06 diagnostic code.

Expected Result:

A 1440-06 diagnostic code is activated.

Results:

• OK - When the wiring for the throttle actuator was replaced with a short circuit, a 1440-06 diagnostic code was activated by the ECM. The ECM is operating correctly. The problem appears to be resolved. The initial diagnostic code was probably caused by a poor electrical connection.

  Repair: Perform the following procedure:

  Set the engine control to the OFF mode. Switch the 16 amp circuit breaker OFF.

  Remove the jumper wire from the P2 connector.

  Reinstall the terminals that were removed from the P2 connector. Pull on the wires in order to verify proper installation of the terminals.

  Reconnect all of the connectors. Verify that the problem is resolved.

  STOP

• Not OK - When the wiring for the throttle actuator is replaced with a short circuit, a 1440-06 diagnostic code is not activated by the ECM. The ECM may have a problem.

  Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this procedure again. If the problem is not resolved, perform the following procedure:

  Temporarily install a new ECM. Refer to Troubleshooting, "Replacing the ECM".

  If the problem is resolved with a new ECM, install the original ECM and verify that the problem returns. If the new ECM operates correctly and the original ECM does not operate correctly, replace the original ECM. Follow the instructions in Troubleshooting, "Replacing the ECM".

  STOP