3500B Series II Marine Engines Caterpillar

The 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, 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 position. Next, turn the ECS to the STOP position. Then turn the ECS to the START position.

After the ECS is placed in the START position, the ECM will begin the prelube cycle. The ECM will send a signal to terminal BH of the customer connector after the prelube cycle is complete. The engine start signal will return on terminal BJ of the customer connector to the starting motor relays "SMMS1" and "SMMS2". The starting motor relays will energize closing the normally open contacts of the relays. Current will flow to the starting motors. The starting motors will begin to crank the engine.

The engine can be manually started by using the "crank override switch" which is located on the inside of the instrument panel.

Illustration 1	g01186738
Typical example

Test Step 1. Check for Connector Damage.

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

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

3. 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.

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

5. Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Inspecting Electrical Connectors" for the correct torque values.

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 OK. 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.

Note: After the ECS is placed in the START position, the ECM will begin the prelube cycle. The ECM will send a signal to terminal BH of the customer connector after the prelube cycle is complete. The engine start signal will return on terminal BJ of the customer connector to the starting motor relays "SMMS1" and "SMMS2". The prelube cycle can be disabled by setting the duration of the prelube cycle to 0.

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

2. Turn the ECS to the STOP position.

3. Connect Cat ET to the service tool connector.

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

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

   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 displays "CRANK". The engine cranks.

Results:

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

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

  STOP

• Not OK - Engine Doesn't Crank - The "startup mode" parameter on the status screen on 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 Cat ET does not display "CRANK".

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

  STOP

Test Step 3. Check the Start Signal at the Customer Connector.

1. Connect one end of a voltmeter to the −Battery terminal. Connect the other end of the voltmeter to wire F701 on terminal BJ of the customer connector.

2. Turn the ECS to the START position.

3. Monitor the voltage on the voltmeter.

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

Expected Result:

The voltage is 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. Proceed to Test Step 5.

• Not OK - The voltage is not 24 ± 3 VDC. Proceed to Test Step 4.

Test Step 4. Check the Start Signal at the Primary ECM.

1. Disconnect the primary ECM connector J2/P2.

2. Remove wire G701 from the primary ECM connector P2-6. Install a wire jumper into P2-6.

3. Reconnect the primary ECM connector J2/P2.

4. Connect one end of a voltmeter to the −Battery terminal. Connect the other end of the voltmeter to the wire jumper in P2-6.

5. Turn the ECS to the START position.

6. Monitor the voltage on the voltmeter.

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

8. Remove the wire jumper and replace all wires.

Expected Result:

The voltage is 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC.

  Repair: Check wire G701 for continuity between ECM connector P2-6 and terminal BH of the customer connector. If necessary, repair the wire. If wire G701 is OK, repair the wiring or devices on the customer's side of the customer connector.

  STOP

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

  Repair: The problem may be in the ECM. Check the electrical power to the ECM. Refer to the diagnostic functional test Troubleshooting, "Electrical Power Supply".

  STOP

Test Step 5. Check the Start Signal to "SMMS1" and "SMMS2" at the Rigid Harness.

1. Connect one end of a voltmeter to the −Battery terminal. Connect the other end of the voltmeter to wire F701 on terminal f of connector "P-C2" of the rigid harness.

2. Turn the ECS to the START position.

3. Monitor the voltage on the voltmeter.

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

Expected Result:

The voltage is 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. Proceed to Test Step 6.

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

  Repair: Repair the wire F701 between terminal BJ of the customer connector and terminal f of connector "P-C2" of the rigid harness.

  STOP

Test Step 6. Check the Voltage from "SMMS1" and "SMMS2" at the Rigid Harness.

1. Connect one end of a voltmeter to the −Battery terminal. Connect the other end of the voltmeter to wire 304 on terminal O of connector "P-C2" of the rigid harness.

2. Turn the ECS to the START position.

3. Monitor the voltage on the voltmeter.

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

5. Connect one end of a voltmeter to the −Battery terminal. Connect the other end of the voltmeter to wire 314 on terminal R of connector "P-C2" of the rigid harness.

6. Turn the ECS to the START position.

7. Monitor the voltage on the voltmeter.

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

Expected Result:

The voltage is 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. Proceed to Test Step 10.

• Not OK - The voltage is not 24 ± 3 VDC. Proceed to Test Step 7.

Test Step 7. Check the Voltage at the Coil of "SMMS1" and the Coil of "SMMS2".

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

2. Connect a voltmeter at the coil of "SMMS1". Connect the voltmeter between terminal 3 of "SMMS1" and engine ground.

3. Turn the ECS to the START position.

4. Monitor the voltage on the voltmeter.

5. Repeat the above steps for "SMMS2".

6. Turn the ECS to the STOP position.

Expected Result:

The voltage is 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. Proceed to Test Step 8.

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

  Repair: Repair the wire F701 between the diode and terminal f of connector "P-C2" of the rigid harness or repair the wire G701 between the diode and terminal 3 of "SMM2". Verify that the diode is working properly.

  STOP

Test Step 8. Check the Voltage across the Coil of "SMMS1" and across the Coil of "SMMS2".

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

2. Connect a voltmeter across the coil of "SMMS1". Connect the voltmeter between terminal 4 and terminal 3 of "SMMS1".

3. Turn the ECS to the START position.

4. Monitor the voltage on the voltmeter.

5. Repeat the above steps for "SMMS2".

6. Turn the ECS to the STOP position.

Expected Result:

The voltage is 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC.

  Repair: Verify that 24 ± 3 VDC is present on terminal 1 of "SMMS1" or on terminal 1 of "SMMS2". If voltage is not present on terminal 1 of "SMMS1" or on terminal 1 of "SMMS2", check the wire A291 between terminal 1 of the starter magnetic switches and the "Starter and Alternator" breaker. Verify that the "Starter and Alternator" breaker is functioning properly.

  If voltage is present on terminal 1, proceed to Test Step 9.

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

  Repair: The problem is in the wire G229 between terminal 4 of "SMMS1" or "SMMS2" and the ECM. Check the wire G229 for continuity between terminal 4 of "SMMS1" or "SMMS2" and the ECM connector P2-7. Repair the wire or replace the wire.

  STOP

Test Step 9. Check the Voltage to the Rigid Harness from the Starter Motor Magnetic Switches.

1. Connect one end of a voltmeter to the −Battery terminal. Connect the other end of the voltmeter to wire 314 on terminal 2 of "SMMS2".

2. Turn the ECS to the START position.

3. Monitor the voltage on the voltmeter.

4. Turn the ECS to the STOP position.

5. Connect one end of a voltmeter to the −Battery terminal. Connect the other end of the voltmeter to wire 304 on terminal 2 of "SMMS1".

6. Turn the ECS to the START position.

7. Monitor the voltage on the voltmeter.

8. Turn the ECS to the STOP position.

Expected Result:

The voltage is 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC.

  Repair: Repair the wire 314 between terminal 2 of "SMM2" and terminal R of connector "P-C2" of the rigid harness or the wire 304 between terminal 2 of "SMM1" and terminal O of connector "P-C2" of the rigid harness. Repair the wires or replace the wires.

  STOP

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

  Repair: Replace either relay "SMM2" or relay "SMM2".

  STOP

Test Step 10. Check the Voltage at the Starting Motor.

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

2. Connect one end of a voltmeter to the −Battery terminal. Connect the other end of the voltmeter to wire 314 on terminal S of the starting motor.

3. Turn the ECS to the START position.

4. Monitor the voltage on the voltmeter.

5. Turn the ECS to the STOP position.

6. Connect one end of a voltmeter to the −Battery terminal. Connect the other end of the voltmeter to wire 304 on terminal S of the starting motor.

7. Turn the ECS to the START position.

8. Monitor the voltage on the voltmeter.

9. Turn the ECS to the STOP position.

Expected Result:

The voltage is 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. The starting motor did not activate. The problem appears to be in the starting motor.

  Repair: Temporarily install a new starting motor. Verify that the problem is no longer present. Reinstall the old starting motor. If the problem returns, replace the starting motor.

  STOP

• OK - The voltage is 24 ± 3 VDC. The starting motor activated.

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

  STOP

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

  Repair: The problem is in the wire 314 between the starting motor and terminal R of connector "P-C2" of the rigid harness or in the wire 304 between the starting motor and terminal O of connector "P-C2" of the rigid harness. Repair the wires or replace the wires.

  STOP