3512B Engine for SPF343, SPS343, and SPT343 Pumpers Caterpillar

The Electronic Control Module (ECM) has the ability to crank the engine when the circuits for the "Deck Start/Run/Kill" switch are complete. 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 start-up mode on the Caterpillar Electronic Technician (ET) will display "OVERCRANK". The engine control will be in an idle state.

When the "Deck Start/Run Kill" switch is turned to the START position the "Start Deck Engine Relay" energizes. A set of normally open contacts from the "Start Deck Engine Relay" close. This changes the Start/Run/Stop inputs to the ECM from a high state to a low state. The ECM energizes the "Start Relay" through the "Start Enable Relay" output. A set of normally open contacts from the "Start Relay" close energizing the "Start Deck Engine Solenoid". Refer to Illustration 1.

Illustration 1	g00855475
Typical example

Test Step 1. Check for Connector Damage.

1. Turn the circuit breaker CB-8 to the OFF position.

2. Turn the main disconnect switch 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 ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).

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

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

Expected Result:

The connectors and wiring should be free of the following problems: damage, corrosion, abrasion and incorrect attachment.

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.

  Stop.

Test Step 2. Attempt to Start the Engine

1. Start the Cat ET.

2. Turn the main disconnect switch to the ON position.

3. Turn the main power switch to the ON position.

4. Turn the circuit breaker CB-8 to the ON position.

5. Turn the "Deck Start/Run Kill" switch to the START position.

Note: If the engine is equipped with a prelubrication system, the engine will not start until the cycle for the prelubrication system is finished. 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.

6. Observe the start-up mode parameter on the Cat ET status screen.

7. Turn the "Deck Start/Run Kill" switch to the "Kill" position.

Expected Result:

The Cat ET status screen for the start-up mode parameter should display "CRANK".

Results:

• OK - The start-up mode parameter on the status screen of the electronic service tool displays "CRANK". The "Start Deck Engine Solenoid" energizes.

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

  Stop.

• Not OK - The start-up mode parameter on the Cat ET status screen displays "CRANK". The "Start Deck Engine Solenoid" does not energize. Proceed to test step 3.

• Not OK - The start-up mode parameter on the Cat ET status screen does not display "CRANK".

  Repair: The ECM did not receive the correct signal from the "Deck Start/Run Kill" switch. Perform the diagnostic functional test Troubleshooting, "Deck Start/Run/Kill Switch".

  Stop.

Test Step 3. Check the Voltage at the "START" Relay Coil.

1. Connect a voltage test lamp between terminal 13 of the "START" relay and engine ground.

2. Activate the override for the starting motor relay on Cat ET.

3. Monitor the voltage test lamp.

4. Deactivate the override for the starting motor relay on Cat ET.

Expected Result:

The voltage test lamp should illuminate.

Results:

• OK - The voltage test lamp illuminates. Proceed to test step 4.

• Not OK - The voltage test lamp does not illuminate. Proceed to test step 6.

Test Step 4. Check the Voltage from the Contacts of the "START" Relay.

1. Activate the override for the starting motor relay on Cat ET.

2. Check the voltage from terminal 6 of the "START" relay to engine ground.

3. Deactivate the override for the starting motor relay on Cat ET.

4. Turn the circuit breaker CB-8 to the OFF position.

Expected Result:

The voltage should measure 12 ± 1 VDC.

Results:

• OK - The voltage is 12 ± 1 VDC. Proceed to test step 5.

• Not OK - The voltage is not 12 ± 1 VDC. Proceed to test step 7.

Test Step 5. Check the Voltage at the "Start Deck Engine Solenoid".

1. Disconnect the connector at the "Start Deck Engine Solenoid".

2. Turn the circuit breaker CB-8 to the ON position.

3. Activate the override for the starting motor relay on Cat ET.

4. Check the voltage from terminal 1 of the "Start Deck Engine Solenoid" and engine ground.

5. Deactivate the override for the starting motor relay on Cat ET.

6. Turn the circuit breaker CB-8 to the OFF position.

Expected Result:

The voltage should measure 12 ± 1 VDC.

Results:

• OK - The voltage measures 12 ± 1 VDC.

  Repair: Check continuity between the wire on terminal 2 of the "Start Deck Engine Solenoid" and engine ground. If the wire is okay, replace the "Start Deck Engine Solenoid". Verify that the system is working correctly.

  Stop.

• Not OK - The voltage does not measure 12 ± 1 VDC.

  Repair: There is a problem in the wiring and/or connectors between terminal 6 of the "START" relay and the "Start Deck Engine Solenoid". Repair the connectors or wiring and/or replace the connectors or wiring.

  Stop.

Test Step 6. Check the Voltage from the ECM to the "START" Relay.

1. Turn the circuit breaker CB-8 to the OFF position.

2. Remove wire F701-OR/BK from ECM connector P2-13. Install a wire jumper into the socket P2-13.

3. Connect a voltage test lamp between the wire jumper in P2-13 and engine ground.

4. Turn the circuit breaker CB-8 to the ON position.

5. Activate the override for the starting motor relay on Cat ET.

6. Monitor the voltage test lamp.

7. Deactivate the override for the starting motor relay on Cat ET.

8. Turn the circuit breaker CB-8 to the OFF position.

9. Remove the jumper wire in P2-13 and reconnect all wires and connectors.

Expected Result:

The voltage test lamp should illuminate.

Results:

• OK - The voltage test lamp illuminates.

  Repair: There is a problem in the wiring and/or connectors between terminal 13 of the "START" relay and ECM connector P2-13. Repair the connectors or wiring and/or replace the connectors or wiring. Verify that the system is working correctly.

  Stop.

• Not OK - The voltage test lamp does not illuminate.

  Repair: There is a problem with the ECM. Replace the ECM. Perform the diagnostic procedure Troubleshooting, "Replacing the ECM".

  Stop.

Test Step 7. Check the Voltage to the Normally Open Contacts on the "START" Relay.

1. Turn the circuit breaker CB-8 to the ON position.

2. Activate the override for the starting motor relay on Cat ET.

3. Check the voltage from terminal 10 of the "START" relay to engine ground.

4. Deactivate the override for the starting motor relay on Cat ET.

5. Turn the circuit breaker CB-8 to the OFF position.

Expected Result:

The voltage should measure 12 ± 1 VDC.

Results:

• OK - The voltage is 12 ± 1 VDC.

  Repair: Check continuity of the wire between terminal 14 of the "START" relay and ECM connector P2-07. If the wire is okay, the "START" relay is the problem. Replace the "START" relay. Verify that the system is working correctly.

  Stop.

• Not OK - The voltage is not 12 ± 1 VDC. Proceed to test step 8.

Test Step 8. Check the Voltage to the "Master Power Solenoid (MPS)".

1. Check the voltage from the positive terminal of the "MPS" to engine ground.

Expected Result:

The voltage should measure 12 ± 1 VDC.

Results:

• OK - The voltage measures 12 ± 1 VDC. Proceed to test step 9.

• Not OK - The voltage does not measure 12 ± 1 VDC. Proceed to test step 10.

Test Step 9. Check the Voltage at the Contacts of the "Master Power Solenoid (MPS)".

1. Check the voltage from terminal 3 of the "MPS" to engine ground.

Expected Result:

The voltage should measure 12 ± 1 VDC.

Results:

• OK - The voltage measures 12 ± 1 VDC.

  Repair: Verify that CB-3 is not tripped. If CB-3 is okay, the wiring and/or connectors between terminal 3 of the "MPS" and terminal 10 of "START" relay need repair. Repair the connectors or wiring and/or replace the connectors or wiring. Verify that the system is working correctly.

  Stop.

• Not OK - The voltage does not measure 12 ± 1 VDC.

  Repair: Check continuity of the wire on the negative terminal of the "MPS" and engine ground. If the wire is okay, replace the "MPS". Verify that the system is working correctly.

  Stop.

Test Step 10. Check the Voltage at the "Main Disconnect Switch (MDS)".

1. Check the voltage from terminal 2 of the "MDS" to engine ground.

Expected Result:

The voltage should measure 12 ± 1 VDC.

Results:

• OK - The voltage measures 12 ± 1 VDC.

  Repair: Verify that CB-2 is not tripped. If CB-2 is okay, the wiring and/or connectors between CB-2 and the positive terminal of "MPS" need repair. Repair the connectors or wiring and/or replace the connectors or wiring. Verify that the system is working correctly.

  Stop.

• Not OK - The voltage does not measure 12 ± 1 VDC.

  Repair: Verify that CB-1 is not tripped. If CB-1 is okay, the wiring and/or connectors between "MDS" and the + Battery terminal need repair. Repair the connectors or wiring and/or replace the connectors or wiring. Verify that the system is working correctly.

  Stop.