3406E and 3456 Generator Set Engines Caterpillar

The Electronic Control Module (ECM) receives four input signals from the Engine Control Switch (ECS). The input signals allow the control to determine the mode of operation. The ECS can operate in four modes: OFF/RESET, MAN/START, COOLDOWN/STOP and AUTO.

When the ECS is set to the OFF/RESET position, the start/run/stop input to the ECM and the auto input to the ECM are open. The ECM is not powered. Engine operation will stop when the ECS is switched to this position.

When the ECS is set to the AUTO position, the start/run/stop input to the ECM is open and the auto input to the ECM is low. The ECM is powered. If the remote start/run/stop switch is closed, the engine start sequence will begin.

When the ECS is set to the MAN/START position, the start/run/stop input to the ECM is low and the ECS in auto input to the ECM is open. The ECM will begin the engine start sequence.

When the ECS is set to the COOLDOWN/STOP position, the start/run/stop input to the ECM is open and the ECS in auto input is open. After the engine cooldown, the ECM will shut down the engine.

If the signals from the start/run/stop input to the ECM are in opposite states, the ECM determines that one of the signals is faulty. The ECM ignores the signals until power is cycled to the ECM. If this occurs, the engine must be cranked manually. Use the "Manual Crank Switch" which is located inside the electronic instrument panel. When the engine is shutdown, the ECS must be placed in the OFF/RESET position. This will disconnect power to the ECM. A diagnostic code will be active until the ECM is powered down. The status for the ignition switch will display "ABNORMAL DATA" until power to the ECM is cycled.

If the engine is running and the signals from the start/run/stop input to the ECM change to opposite states, the engine will continue to run. The ECM generates a diagnostic code that will remain active until power to the ECM is cycled. When the engine is shutdown, the ECS must be placed in the OFF/RESET position. This will disconnect power to the ECM.

If you close the remote start/stop switch, and the ECS is in the AUTO position, the engine will start. The status for the switch will display "ON" or "OFF". This status of the remote start/stop switch is available on the Caterpillar Electronic Technician (ET) when the ECS is in the AUTO position.

Illustration 1	g01067211
Typical example

Test Step 1. CHECK FOR CONNECTOR DAMAGE.

1. Turn the ECS to the OFF position.

2. Thoroughly inspect the ECM connector J1/P1 and the ECM connector J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.

3. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.

4. Check the ECM connector (allen head screw) for the proper torque of 2.25 ± 0.25 N·m (20 ± 2 lb in).

5. Check the machine connector (allen head screw) for the proper torque of 2.25 ± 0.25 N·m (20 ± 2 lb in).

6. Check the harness and the wiring for abrasion and for pinch points.

Expected Result:

All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion and of pinch points.

Results:

• OK - The connectors and wiring are okay. Proceed to Test Step 2.

• Not OK - The connectors and/or wiring are not okay.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring. If necessary, replace the ECS.

  STOP

Test Step 2. CHECK THE STATUS OF THE ECS ON CAT ET.

1. Turn the circuit breaker for the battery to the ON position.

2. Turn the circuit breaker for the mag relay of the starting motor system to the OFF position.

3. Turn the ECS to the STOP position.

4. Connect Cat ET to the service tool connector.

5. Observe the status for the ignition switch on Cat ET.

Expected Result:

The status for the ECS reads "STOP".

Results:

• OK - The status does display "STOP". The ECS is functioning correctly. Proceed to Test Step 3.

• Not OK - The status does not display "STOP". Proceed to Test Step 4.

Test Step 3. CHECK THE STATUS OF THE ECS IN THE START POSITION.

1. Turn the ECS to the START position.

2. Observe the status for the ignition switch on Cat ET.

Expected Result:

The status for the ignition switch reads "RUN".

Results:

• OK - The status for the ECS does display "RUN". The ECS is working correctly. Proceed to Test Step 5.

• Not OK - The status for the ECS does not display "RUN". Proceed to Test Step 4.

Test Step 4. CHECK THE OUTPUT AT THE ECM.

1. Turn the ECS to the OFF/RESET position.

2. Disconnect ECM connector P1 from the ECM. Remove P1:29 and insert a wire jumper.

   Note: The digital return will no longer be connected to the other sensors and switches. Additional diagnostic codes will be generated from the ECM. Clear the codes after you complete this test.

3. Remove P1:13. Insert a wire jumper into P1:13.

4. Remove P1:14. Insert a wire jumper into P1:14.

5. Reconnect connector P1 to ECM connector J1.

6. Use a wire jumper to connect the jumper wire in P1:29 to the jumper wires in P113 and P1:14.

7. Turn the ECS to the STOP position.

8. Observe the status for the ECS on Cat ET.

9. Turn the ECS to the OFF/RESET position and remove the jumper wire.

Expected Result:

The status for the ECS displays "RUN" while the jumper wire is installed. The status for the ECS displays "STOP" when the jumper wire is removed.

Results:

• OK - The status for the ECS displays the proper states. The problem is not with the ECM.

  Repair: Check continuity of the wiring between the ECM and ECS. Check continuity across the contacts of the ECS.

  Proceed to Test Step 5.

• Not OK - The status for the ECS does not show the correct states.

  Repair: Replace the ECM. Refer to the diagnostic procedure Troubleshooting, "Replacing the ECM".

  STOP

Test Step 5. CHECK THE STATUS OF THE ECS IN THE AUTO POSITION.

1. Turn the ECS to the AUTO position. Place the remote start/stop switch in the START position.

2. Observe the status for the ECS on Cat ET. Observe the status for the remote start on Cat ET.

Expected Result:

The status for the ECS reads "AUTO". The status for the remote start reads "ON".

Note: Some applications may not use a remote start/stop switch.

Results:

• OK - The status for the ECS does display "AUTO". The status for the remote start does read "ON". The ECS and the remote start/stop switch are working correctly.

  Repair: The problem may be intermittent. If the problem is intermittent, refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".

  STOP

• Not OK - Remote Start - The status for the remote start does not display "ON". There is a problem with the wiring between the remote start/stop switch and the ECS. Proceed to Test Step 7.

• Not OK - ECS - The status for the ECS does not display "AUTO". Proceed to Test Step 6.

Test Step 6. CHECK SWITCHES AND WIRING WITH THE ECS IN THE OFF POSITION

1. Turn the ECS to the OFF/RESET position.

2. Disconnect ECM connector P1 from the ECM. Remove P1:24. Insert a wire jumper into P1:24.

   Note: The digital return will no longer be connected to the other sensors and switches. Additional diagnostic codes will be generated from the ECM. Clear the codes after you complete this test.

3. Measure the resistance between P1:29 digital sensor return and P1:14 (Start/run/stop 1).

4. Measure the resistance between P1:29 digital sensor return and P1:13 (Start/run/stop 2).

5. Turn the ECS to the STOP position.

6. Repeat Steps C and D.

7. Turn the ECS to the OFF/RESET position.

8. Remove the jumper wire.

Expected Result:

The resistance is greater than 20,000 Ohms.

Results:

• OK - The resistance is greater than 20,000 Ohms. Proceed to Test Step 7.

• Not OK - There is a short circuit in the wiring for the ECS.

  Repair: Repair the wiring or replace the wiring. Verify that the repair has eliminated the problem.

  STOP

Test Step 7. CHECK THE SWITCHES AND WIRING WITH THE ECS IN THE START POSITION

1. Turn the circuit breaker for the battery to the OFF position.

2. Turn the ECS to the START position.

3. Measure the resistance betweenP1:29 (Digital sensor return) and P1:14 (Start/run/stop 1).

4. Measure the resistance between P1:29 (Digital sensor return) and P1:13 (Start/run/stop 2).

Expected Result:

The resistance reads less than 10 Ohms.

Results:

• OK - The resistance is less than 10 Ohms. Proceed to Test Step 8.

• Not OK - There is an open circuit or excessive resistance in the wiring for the ECS. Repair the wiring or replace the wiring. Verify that the repair has eliminated the problem.

  STOP

Test Step 8. CHECK THE SWITCHES AND THE WIRING WITH ECS IN AUTO POSITION AND THE REMOTE START/STOP SWITCH IN STOP POSITION

1. Turn the ECS to the AUTO position. Verify that the start/stop switch is in the STOP position.

2. Measure the resistance between P1:29 (Digital sensor return) and P1:14 (Start/run/stop 1).

3. Measure the resistance between P1:29 (Digital sensor return) and P1:13 (Start/run/stop 2).

Expected Result:

The resistance is greater than 20,000 Ohms.

Results:

• OK - The ECS is functioning properly. Proceed to Test Step 9.

• Not OK - There is a short circuit in the wiring for the ECS.

  Repair: Repair the wiring or replace the wiring. Verify that the repair has eliminated the problem.

  STOP

Test Step 9. CHECK THE SWITCHES AND THE WIRING WITH ECS IN AUTO AND THE REMOTE START/STOP SWITCH IN START/RUN POSITION

1. Turn the ECS to the AUTO position. Verify that the remote start/stop switch is in the START/RUN position.

2. Measure the resistance between P1:29 (Digital sensor return) and P1:14 (Start/run/stop 1).

3. Measure the resistance between P1:29 (Digital sensor return) and P1:13 (Start/run/stop 2).

Expected Result:

The resistance is less than 10 Ohms.

Results:

• OK - The ECS is functioning properly. Proceed to Test Step 10.

• Not OK - There is an open circuit in the wiring for the ECS.

  Repair: Repair the wiring or replace the wiring. Verify that the repair has eliminated the problem.

  STOP

Test Step 10. CHECK THE OUTPUT AT THE ECM.

1. Turn the ECS to the OFF/RESET position.

2. Disconnect ECM connector P1 from the ECM. Remove P1:29 and insert a wire jumper.

   Note: The digital return will no longer be connected to the other sensors and switches. Additional diagnostic codes will be generated from the ECM. Clear the codes after you complete this test.

3. Remove P1:24. Insert a wire jumper into P1:24.

4. Reconnect connector P1 to ECM connector J1.

5. Turn the ECS to the STOP position.

6. Observe the status for the ECS on Cat ET.

7. Turn the ECS to the OFF/RESET position and remove the jumper wire.

8. Remove the wire jumpers and reconnect all ECM connectors.

Expected Result:

The status for the ECS displays "AUTO" while the jumper wire is installed. The status for the ECS displays "STOP" when the jumper wire is removed.

Results:

• OK - The status for the ECS displays the proper states. The problem is not with the ECM.

  Repair: The problem may be an intermittent electrical problem with the wiring and/or the ECS. Check continuity of the wiring between the ECM and ECS. Check continuity across the contacts of the ECS. Refer to Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - The status for the ECS does not show the correct states.

  Repair: Replace the ECM. Refer to the diagnostic procedure Troubleshooting, "Replacing the ECM".

  STOP