3512B Marine Auxiliary Engine Caterpillar

The engine's Electronic Control Module (ECM) has the ability to crank the engine when the Engine Control Switch (ECS) is placed in the START position. The engine control will start the first crank cycle, when the ECS is placed in the START position. The crank cycle will continue for the time that is equal to the cycle crank time that has been programmed or the crank cycle will continue until the engine speed reaches the crank terminate speed. If crank terminate speed is not reached before the crank cycle time, the starting motor will deactivate at the end of the crank cycle time.

This process will repeat for a programmed amount of times (Total Number of Crank Cycles). If the engine does not start, the Caterpillar Electronic Technician (ET) will display "OVERCRANK". The engine control will be in an idle state. The process can be restarted by turning the ECS to the OFF/RESET. Next turn the ECS to the STOP position. Then turn the ECS to the START position.

The Manual Crank Start switch is located in the instrument panel. The manual crank start switch can be used to crank the engine for troubleshooting purposes. The manual crank start switch will override any other engine controls and/or protective devices. The manual crank start switch can be used to activate the starting motors. The manual crank start switch can be used to start the engine when the secondary ECM is in control of the engine. DO NOT use the manual crank start switch for normal engine operation.

Illustration 1	g00809892

Note: The Engine Control Switch (ECS) is mounted within an instrument panel that is located on the right side of the engine. The ECS is locked into the AUTO position with a pin. The pin must be removed in order to perform this test. After performing this test, ensure that the ECS is placed in the AUTO position and that the locking pin has been reinstalled.

Test Step 1. Check for Connector Damage.

1. Disconnect the main power.

2. Thoroughly inspect the ECM connectors J1/P1 and 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 6.0 N·m (55 lb in).

5. Check the customer 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 pinch points.

Expected Result:

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

Results:

• OK - The connectors and wiring are okay. Proceed to test step 2.

• Not OK - The connectors and/or wiring need repair.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

  Stop.

Test Step 2. Attempt to Start the Engine

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

2. Connect the Cat ET to the service tool connector.

3. Turn the ECS to the STOP position.

4. Observe the "startup mode" parameters on the Cat ET status screen.

5. Turn the ECS to the START position. Continue monitoring engine parameters as the engine cranks.

6. The crank cycle will continue for the time that is equal to the cycle crank time that has been programmed or the crank cycle will continue until the engine speed reaches the crank terminate speed.

Expected Result:

The status screen for the "startup mode" parameter should display "CRANK". The engine cranks.

Results:

• OK - The "startup mode" parameter on the status screen on the Cat ET displays "CRANK". The engine cranks.

  Repair: The circuit is working properly. Check for active diagnostic codes.

  Stop.

• Not OK-Engine Doesn't Crank - The "startup mode" parameter on the status screen on the Cat ET displays "CRANK". The engine will not crank. Proceed to test step 3.

• Not OK-Status Screen - The "startup mode" parameter on the status screen on the Cat ET does not display "CRANK".

  Repair: Perform the diagnostic functional test Troubleshooting, "Engine Control Switch (ECS)".

  Stop.

Test Step 3. Manually Crank the Engine.

1. Turn the ECS to the STOP position.

2. Open the electronic instrument panel.

3. Connect one end of a voltmeter to - Battery terminal. Connect the other end of the voltmeter to wire 304-WH on terminal 2 of the mag relay.

4. Turn the ECS to the STOP position.

5. Activate the manual crank start switch.

6. Monitor the voltage on the voltmeter.

7. Release the manual crank start switch.

Expected Result:

The voltage should measure 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC. Proceed to test step 7.

• Not OK - The voltage does not measure 24 ± 3 VDC. Proceed to test step 4.

Test Step 4. Check the Coil on the Mag Relay.

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

2. Remove wire E779-BR from terminal 4 of the mag relay. Connect one end of the voltmeter to - Battery terminal. Connect the other end of the voltmeter to terminal 4 of the mag relay.

3. Turn the ECS to the STOP position.

4. Activate the manual crank start switch.

   Note: This test will cause a 444-05 CID-FMI to be Logged. Delete this CID-FMI when you are finished with this test.

5. Monitor the voltage on the voltmeter.

6. Release the manual crank start switch.

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

8. Replace all wires.

Expected Result:

The voltage should measure 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC.

  Repair: The problem appears to be with the mag relay. Temporarily install a new mag relay. Verify that the problem is no longer present. Reinstall the old mag relay. If the problem returns, replace the mag relay.

  Stop.

• Not OK - The voltage does not measure 24 ± 3 VDC. Proceed to test step 5.

Test Step 5. Check the ECM Signal at the Mag Relay.

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

2. Connect one end of the voltmeter to the - Battery terminal. Connect the other end of the voltmeter to wire F701-BR on terminal 3 of the mag relay.

3. Turn the ECS to the STOP position.

4. Activate the manual crank start switch.

   Note: This test will cause a 444-05 CID-FMI to be Logged. Delete this CID-FMI when you are finished with this test.

5. Monitor the voltage on the voltmeter.

6. Release the manual crank start switch.

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

Expected Result:

The voltage should measure 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC.

  Repair: The coil of the mag relay is open. Temporarily install a new mag relay. Verify that the problem is no longer present.

  Stop.

• Not OK - The voltage does not measure 24 ± 3 VDC. Proceed to test step 6.

Test Step 6. Check the ECM Signal at the ECM.

1. Disconnect ECM connector P2 at the primary ECM. Remove the wire F701-BR from P2-13. Install a wire jumper with sockets at both ends into P2-13.

2. Remove the wire E799-BR from P2-07. Install a wire jumper with sockets at both ends into P2-07.

3. Reconnect the primary ECM connector J2/P2.

4. Connect one probe of the voltmeter to the wire jumper in P2-7. Connect the other probe of the voltmeter to the wire jumper in P2-13.

5. Turn the ECS to the STOP position.

6. Activate the manual crank start switch.

   Note: This test will cause a 444-05 CID-FMI to be Logged. Delete this CID-FMI when you are finished with this test.

7. Monitor the voltage on the voltmeter.

8. Release the manual crank start switch.

9. Turn the ECS to the OFF/RESET position. Remove all jumpers and replace all wires.

Expected Result:

The voltage should measure 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC.

  Repair: The problem is not with the ECM. The problem is most likely in the wiring between ECM connector P2 and the mag relay.

  Stop.

• Not OK - The voltage does not measure 24 ± 3 VDC.

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

  Stop.

Test Step 7. Check the Solenoid.

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

2. Disconnect the connector J122/P122 for the air start solenoid.

3. Connect one end of a suitable piece of 10 AWG wire to the + Battery terminal. Connect one end of a suitable piece of 10 AWG wire to the - Battery terminal. Use the other end of these wires to activate the start solenoid. Do not activate the solenoid for more than one second.

4. Remove the wires and reconnect connector J122/P122.

Expected Result:

The starting solenoid should activate.

Results:

• OK - The starting solenoid activated. The problem appears to be in the system wiring.

  Repair: Verify that the wire 200-BK from the solenoid connector J122 to the - Battery terminal is not open or shorted to engine ground. Check and repair the wiring between connector J122/P122 of the starting solenoid and terminal 2 of the mag relay. Verify repairs by checking starting solenoid operation.

  Stop.

• Not OK - The starting solenoid did not activate. The problem appears to be in the starting solenoid.

  Repair: Temporarily install a new starting solenoid. Verify that the problem is no longer present.

  Stop.