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

To reduce resistance in the wiring harness, there are two isolated + Battery connections and two isolated - Battery connections to the Electronic Control Module (ECM). The connections must be complete in order to ensure proper engine operation. There is a constant power supply to the ECM when the engine is shutdown. In order to shut off the power to the ECM, the "Main Power Disconnect" switch needs to be turned to the OFF position and the circuit breaker "CB-8" needs to be in the OFF position. The ECM supplies 5 ± 0.2 VDC from the ECM connector P1-36 to each analog sensor connector pin A. The analog return line is from ECM connector P1-30 to each analog sensor connector pin B. The ECM supplies 8 ± 0.4 VDC from the ECM connector P1-35 to each digital sensor connector pin A. The digital return line is from ECM connector P1-29 to each digital sensor connector pin B.

The engine will begin the start-up when the following conditions exist:

• The ECM detects the battery voltage at the keyswitch on P1-23.

• The "Deck Start/Run/Kill" switch is toggled to the START position.

When the "Emergency Kill" switch is activated, the "Emergency Kill Relay" is activated. A set of contacts that are normally closed opens up. The open contacts remove the digital ground from the two emergency shutdown inputs of the ECM. The fuel supply to the injectors will be cut off and the air shutoff relays will be activated.

Note: The "Emergency Kill" switch is activated or ON when the switch is in the ON position. The "Emergency Kill" switch is deactivated or OFF when the "Emergency Kill" switch is in the OFF position.

Note: If welding occurs on the engine or near the engine, be sure to protect the engine electronics from spikes in the voltage. The engine block and the driven equipment should be properly grounded. This will prevent any electrical discharge across the main bearings.

Proper welding procedures are necessary to avoid damage to the electronic control module and associated sensors and components. The guidelines which are listed should be followed when you are welding on any engine or for any application that uses electronic controls. The guidelines for welding follow:

• Stop the engine. Put the "Deck Start/Run/Kill" switch in the "KILL" position.

• Disconnect the ECM connectors, J1 and J2 from the harness.

• Disconnect the negative battery cable at the battery. If a battery disconnect switch is provided, put the switch in the OPEN position. Do not use fuel system components for grounding the welder.

• Connect the clamp for the ground cable of the welder directly to the part. Place this clamp as close as possible to the weld in order to reduce the possibility of damage by the welding current. Components which can be easily damaged include bearings, hydraulic components, and electrical components.

• Protect any wiring harness from welding debris and spatter.

• Use standard welding procedures in order to weld the materials.

Illustration 1	g00856605
Typical example

Test Step 1. Check for Connector Damage.

1. Turn the main disconnect switch to the OFF position.

2. Turn circuit breaker "CB-8" 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 are free of the following problems: damage, abrasion, corrosion and incorrect attachment.

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

  Stop.

Test Step 2. Check for "ACTIVE" Diagnostic Codes

1. Start the Caterpillar Electronic Technician (ET).

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

3. Turn circuit breaker "CB-8" to the ON position.

4. Determine if you have either of the following active diagnostic codes:
   • CID-FMI 168-00 System Voltage High

   • CID-FMI 168-01 System Voltage Low

Expected Result:

One of the diagnostic codes is present.

Results:

• OK - One of the diagnostic codes is present. Proceed to test step 3.

• Not OK - One of the diagnostic codes is not present. Proceed to test step 4.

Test Step 3. Check the Battery Voltage.

1. Turn the main disconnect switch to the OFF position.

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

3. Measure no-load voltage at the battery posts. Refer to Testing and Adjusting, "Test Tools for the Electrical System" for the proper procedures to check the batteries.

4. Load test the batteries. Use the 4C-4911 Battery Load Tester. Refer to the Operating Manual, SEHS9249. Refer to Special Instruction, SEHS7633.

Expected Result:

The no-load voltage at the batteries should be at least 23.5 VDC, and the batteries should pass the load test.

Results:

• OK - The no-load voltage at the batteries is at least 23.5 VDC, and the batteries pass the load test. Proceed to test step 4.

• Not OK - The no-load voltage at the batteries is less than 23.5 VDC, and/or the batteries fail the load test.

  Repair: The batteries or the alternator are causing the problem. Recharge the batteries or replace the batteries. Refer to Testing and Adjusting, "Initial Troubleshooting Procedure". Verify that the original condition is resolved.

  Stop.

Test Step 4. Check for Battery Voltage to the ECM.

1. Turn the main disconnect switch to the OFF position.

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

3. Remove ECM connector J1/P1.

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

5. Measure the voltage at ECM connector J1/P1 between pins P1-04 and P1-11.

6. Measure the voltage at ECM connector J1/P1 between pins P1-06 and P1-05.

Expected Result:

The voltage should measure 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC. Proceed to test step 5.

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

  Repair: There is a problem with the wiring and/or connectors between the battery and the ECM. Verify that circuit breaker "CB-8" is not tripped. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

Test Step 5. Check the Voltage to the Input for the Keyswitch on the ECM.

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

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

3. Measure the voltage at the ECM connector J1/P1 between pins P1-23 and P1-11.

Expected Result:

The voltage should measure 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC. Proceed to test step 8.

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

Test Step 6. Check the Voltage from the Contacts of the "Main Disconnect Relay".

1. Use a voltmeter to check the voltage between terminal 5 on the "main disconnect relay" and engine ground.

Expected Result:

The voltage should measure 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC.

  Repair: There is a problem in the harness and/or connectors between terminal 5 of the "main disconnect relay" and the ECM. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

• Not OK - The voltage does not measure 24 ± 3 VDC. Proceed to test step 7.

Test Step 7. Check the Voltage to the Coil of the "Main Disconnect Relay".

1. Use a voltmeter to check the voltage between terminal 13 of the "main disconnect relay" and engine ground.

2. Use a voltmeter to check the voltage between terminal 9 on the "main disconnect relay" and engine ground.

Expected Result:

The voltage should measure 12 ± 1 VDC on terminal 13 of the "main disconnect relay". The voltage should measure 24 ± 3 VDC on terminal 9 of the "main disconnect relay".

Results:

• OK - The voltage measures 12 ± 1 VDC.

  Repair: Verify that the wire on terminal 14 of the "main disconnect relay" has continuity to the - Battery terminal. Replace the "main disconnect relay". Verify that the problem is no longer present.

  Stop.

• Not OK - Terminal 9 - The voltage does not measure 24 ± 3 VDC.

  Repair: There is a problem with the wiring and/or connectors between the battery and terminal 9 of the "main disconnect relay". Verify that circuit breaker "CB-8" is not tripped. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

• Not OK - Terminal 13 - The voltage does not measure 12 ± 1 VDC.

  Repair: There is a problem in the harness and/or connectors between the "main disconnect relay" and the Battery. Check the main disconnect switch and circuit breaker CB-1 for proper operation. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

Test Step 8. Check the Voltage at the Input to the ECM for the "Emergency Kill" Switch.

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

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

3. Connect a voltage test lamp between pins P1-02 and P1-29 at ECM connector P1.

4. Connect a voltage test lamp between pins P1-20 and P1-29.

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

6. Turn the main disconnect switch to the OFF position.

Expected Result:

The voltage test lamp should not be illuminated.

Results:

• OK - The voltage test lamp is not illuminated. Proceed to test step 9.

• Not OK - The voltage test lamp is illuminated.

  Repair: The Emergency Stop circuit has been activated or the emergency stop circuit has an open circuit. Verify that the "Emergency Kill" switch is not activated. Check the "Emergency Kill" switch for proper operation. Check that the "Left Air Shutoff Switch (LSOS)" and the "Right Air Shutoff Switch (RSOS)" are closed. There may be a problem in the wiring and/or connectors. Repair the connectors and/or wiring or replace the connectors and/or wiring.

  Stop.

Test Step 9. Check the Analog Voltage Supply and the Digital Voltage Supply from the ECM.

1. Disconnect ECM connector J1/P1.

2. Remove the following wires from ECM connector P1: 997-WH on pin 36, 993-BK on pin 30, A700-WH on pin 35 and 998-BK on pin 29. Install wire jumpers into the sockets for each of the above wires that were removed from P1.

   Note: Disconnecting the common sensor wire of the sensor supplies from the ECM will generate an open circuit diagnostic code for all sensors that are connected to the sensor common. Troubleshoot the original diagnostic code. Delete the logged diagnostic codes when you are finished.

3. Reconnect ECM connector P1.

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

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

6. Measure the voltage between the wire jumpers in pin 36 and pin 30. This is the analog voltage supply.

7. Measure the voltage between the wire jumpers in pin 35 and pin 29. This is the digital voltage supply.

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

9. Turn the main disconnect switch to the OFF position.

10. Remove the wire jumpers and reconnect all wires and connectors.

Expected Result:

The analog voltage supply should measure 5 ± 0.2 VDC. The digital voltage supply should measure 8 ± 0.4 VDC.

Results:

• OK - The analog voltage supply measures 5 ± 0.2 VDC. The digital voltage supply measures 8 ± 0.4 VDC.

  Repair: The electrical power to the ECM is correct. The ECM is generating the correct analog supply voltage and the correct digital supply voltage. There may be an intermittent problem. Perform the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" if the problem returns.

  Stop.

• Not OK - The analog voltage supply does not measure 5 ± 0.2 VDC. The digital voltage supply does not measure 8 ± 0.4 VDC.

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

  Stop.