3512B Marine Auxiliary Engine Caterpillar

The Electronic Control Module (ECM) has the ability to crank the engine when the Engine Control Switch (ECS) is placed in the BLACK START ENABLE position. The engine control will start the first crank cycle, when the ECS is placed in the BLACK START ENABLE position. When the BLACK START ENABLE push button is depressed, 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 cycle crank time, the starting motor will deactivate for a time that is equal to the cycle crank 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 BLACK START ENABLE position.

Illustration 1	g00926369

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. Perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".

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, abrasion or 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 of the Cat ET displays "CRANK". The engine cranks. Stop.

• Not OK-Engine Doesn't Crank - The "startup mode" parameter on the status screen of 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 of 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 the - 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 START position.

5. Activate the manual crank switch.

6. Monitor the voltage on the voltmeter.

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 the - 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 override for the starting motor relay.

   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. Turn off the override for the starting motor relay.

7. 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 override for the starting motor relay.

   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. Turn off the override for the starting motor relay.

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. Turn the ECS to the OFF/RESET position.

2. Disconnect ECM connector P2 at the primary ECM. Remove the wire from P2-7 and P2-13.

3. Install a Breakout T at ECM connector P2.

4. Connect one probe of the voltmeter to pin P2-7 at the Breakout T. Connect the other probe of the voltmeter to pin P2-13 at the Breakout T.

5. Turn the ECS to the STOP position.

6. Activate the override for the starting motor relay.

   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. Turn off the override for the starting motor relay.

8. 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. Perform 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 while the wire is connected to J122/P122.

Results:

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

  Repair: Verify that the circuit breaker for the mag relay has not tripped. 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.