C32 Marine Auxiliary Engines Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the starting system or if one of the diagnostic codes in Table 1 is active.

In order to crank the engine, the ECM will send a signal to the Starting Motor Magnetic Switch (SMMS). Current will flow to the starting motor through the contacts of the SMMS. The starting motor will begin to crank the engine.

Engine cranking can be initiated by several methods. The ECM can receive a request in order to crank the engine over the CAN data link from a device such as the Electronic Modular Control Panel 3 (EMCP 3). The ECM can receive a request in order to crank the engine from a hard wired switch input at J1-47. The SMMS can be energized directly by the crank override switch. The SMMS can be energized directly by an external starting motor control. Be sure that the "Engine State Control Input Configuration" is configured for the correct type of system. Refer to Troubleshooting, "Configuration Parameters".

The ECM has ultimate control over the SMMS when the return current wire is connected to the J2-19 starter interlock terminal. This is done by controlling the sinking driver at the J2-19 starter interlock terminal of the ECM. This allows the ECM to prevent unwanted engagement of the starter gear to a moving flywheel ring gear regardless of the device that is sourcing current to the SMMS.

When the ECM receives a request for starting the engine the ECM will first begin the process of engine prelubrication. When the engine prelubrication is complete, the ECM will start the first crank cycle.

Note: If the configuration parameter "Prelube Duration" is set to zero seconds, the ECM will skip the process of prelubrication. The ECM will begin cranking the engine immediately. Refer to Troubleshooting, "Configuration Parameters" for the available range and default setting of this parameter.

The ECM will crank the engine until the programmed "Crank Terminate Speed" has been reached. If the engine fails to reach the "Crank Terminate Speed" before the programmed "Crank Duration" period the ECM will stop cranking the engine. The ECM will then allow the starter to cool for a period that is equal to the "Crank Duration" before starting the next crank cycle. The process will be repeated for a number of times that is equal to the programmed "Maximum Number of Crank Cycles". When the "Maximum Number of Crank Cycles" has been reached, the process will be aborted and Caterpillar Electronic Technician (ET) will display "OVERCRANK". The process will be restarted when the next start request is received by the ECM.

Refer to Troubleshooting, "Configuration Parameters" for the available ranges and default settings of the following parameters:

• "Crank Duration"

• "Crank Terminate Speed"

• "Maximum Number of Crank Cycles"

Note: If the "Crank Duration" or "Maximum Number of Crank Cycles" are programmed to 0 the ECM will not crank the engine.

The engine can be manually started by using the customer's keyswitch or the crank override switch while keyswitch power is applied to J1-70 of the ECM.

Illustration 1	g01407953
Typical schematic

Illustration 2	g01408104
P2 ECM connector (59) Crank + (sourcing driver for the SMMS) (19) Starter Interlock (sinking driver for SMMC )

Illustration 3	g01408117
P1 ECM connector (P1-47) Momentary start switch input (P1-49) Momentary stop switch input (P1-63) -Battery (P1-70) Keyswitch

Illustration 4	g01408156
Location of ECM connectors (1) P2/J2 (2) P1/J1

Test Step 1. Inspect Electrical Connectors and Wiring

1. Remove electrical power from the ECM.

2. Thoroughly inspect the ECM connectors. Inspect all of the other connectors for the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" 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. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

5. 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. 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 - There is a problem in the connectors and/or wiring.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.

  STOP

Test Step 2. Check for Active Diagnostic Codes for the SMMS

1. Connect Cat ET to the service tool connector.

2. Restore electrical power to the ECM.

3. Monitor the active diagnostic code screen on Cat ET. Check for an active -5 diagnostic code for the SMMS.

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

4. Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the override for the starting system.

5. Monitor the active diagnostic code screen on Cat ET. Check for a -6 diagnostic code for the SMMS.

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

6. Deactivate the override for the starting system.

Expected Result:

No diagnostic codes are active.

Results:

• OK - No diagnostic codes are active, but a problem is suspected in the starting system. Proceed to Test Step 6.

• Not OK - A -6 diagnostic code is active at this time. Proceed to Test Step 3.

• Not OK - A -5 diagnostic code is active at this time. Proceed to Test Step 4.

Test Step 3. Create an Open at the Coil of the SMMS

1. Disconnect the wires from terminal 1 and terminal 2 on the SMMS or disconnect the connectors for the SMMS, if equipped. Ensure that the wires are isolated from engine ground and from sources of electrical power.

2. Monitor the active diagnostic code screen on Cat ET. Check for a -5 diagnostic code for the SMMS.

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

3. Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the override for the starting system.

4. Monitor the active diagnostic code screen on Cat ET. Check for a -6 diagnostic code for the SMMS.

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

5. Deactivate the override for the starting system.

Expected Result:

A -5 diagnostic code is now active for the starting motor system.

Results:

• OK - A -5 diagnostic code became active after creating the open at the SMMS. The wires from the ECM to the SMMS are OK.

  Repair: The problem may be in the coil of the SMMS. Install a new SMMS. Clear any logged diagnostic codes.

  STOP

• Not OK - A -6 diagnostic code remains active. There is a short between the SMMS and the ECM. Leave the wires for the SMMS disconnected. Proceed to Test Step 5.

Test Step 4. Create a Short at the Coil of the SMMS

1. Install a jumper wire between terminal 1 and terminal 2 at the SMMS.

2. Monitor the active diagnostic code screen on Cat ET. Check for a -5 diagnostic code for the SMMS.

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

3. Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the override for the starting system.

4. Monitor the active diagnostic code screen on Cat ET. Check for a -6 diagnostic code for the SMMS.

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

5. Deactivate the override for the starting system.

Expected Result:

A -6 diagnostic code is active when the jumper wire is installed.

Results:

• OK - A -6 diagnostic code is active when the jumper wire is installed. The wires from the ECM to the SMMS are OK.

  Repair: The problem may be in the coil of the SMMS. Install a new SMMS. Clear any logged diagnostic codes.

  STOP

• Not OK - The -5 diagnostic code is active when the sourcing driver for the SMMS is not activated. A -6 code does not activate when the override for the starting system is activated with the jumper in place. The open circuit is between the ECM and the SMMS. Proceed to Test Step 5.

Test Step 5. Test the Operation of the ECM

1. Fabricate a jumper wire that can be used to replace the wire in the ECM connector for the SMMS. Crimp a connector socket to one end of the jumper wire.

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

3. Disconnect the appropriate ECM connector for the SMMS.

4. Remove the wire for the SMMS from the ECM connector.

5. Install the jumper wire into the terminal location for the SMMS at the ECM connector.

6. Connect the ECM connector.

7. Check the operation of the ECM by creating an open at the ECM:

   1. Hold the loose end of the jumper wire away from any components in order to create an open circuit condition.

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

   3. Monitor the active diagnostic code screen on Cat ET. Check for a -5 diagnostic code for the SMMS.

      Note: Wait at least 30 seconds in order for the diagnostic code to become active.

   4. Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the override for the starting system.

   5. Monitor the active diagnostic code screen on Cat ET. Check for a -6 diagnostic code for the SMMS.

      Note: Wait at least 30 seconds in order for the diagnostic code to become active.

   6. Deactivate the override for the starting system.

8. Check the operation of the ECM by creating a short circuit at the ECM:

   1. Short the jumper wire for the SMMS to engine ground.

   2. Monitor the active diagnostic code screen on Cat ET. Check for a -5 diagnostic code for the SMMS.

      Note: Wait at least 30 seconds in order for the diagnostic code to become active.

   3. Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the override for the starting system.

   4. Monitor the active diagnostic code screen on Cat ET. Check for a -6 diagnostic code for the SMMS.

      Note: Wait at least 30 seconds in order for the diagnostic code to become active.

   5. Deactivate the override for the starting system.

9. Remove electrical power from the ECM. Reconnect all wires to the original configuration.

Expected Result:

A -5 diagnostic code is active when the wire for the SMMS is open at the ECM connector. A -6 diagnostic code is active when the wire for the SMMS is shorted at the ECM connector.

Results:

• OK - The ECM is operating properly. The problem is in the wiring between the ECM and the SMMS.

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

  STOP

• Not OK - One of the following conditions exists: The -5 diagnostic code is not active when the wire for the SMMS is disconnected. The -6 diagnostic code is not active when the wire jumper is installed.

  Repair: Replace the ECM. Refer to Troubleshooting, "ECM - Replace". Verify that the problem is resolved.

  STOP

Test Step 6. Check the Voltage at the Plus Battery Side of the Normally Open Contacts of the SMMS

1. Measure the voltage between terminal 4 of the SMMS and engine ground.

Expected Result:

The voltage measures 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.

  Repair: The problem appears to be in the wiring between the +Battery terminal and the SMMS. Verify that any breaker between the SMMS and the +Battery terminal is not tripped. Repair the connectors or wiring and/or replace the connectors or wiring.

  STOP

Test Step 7. Check the Voltage from the SMMS to the Starting Motor.

1. Remove the wire from terminal 3 of the SMMS.

2. Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the override for the starting system.

3. Measure the voltage between terminal 3 on the SMMS and engine ground while the override is active.

4. Deactivate the override for the starting system.

5. Restore the wiring to the original configuration.

Expected Result:

The voltage measures 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.

  Repair: Voltage is present at the normally open contacts of the SMMS. There are no diagnostic codes for the SMMS. Voltage is not present on the wire going to the starting motors. Replace the SMMS.

  STOP

Test Step 8. Check the Voltage at the Starting Motors

1. Disconnect the wire that leads from terminal 3 of the SMMS at the starter solenoid.

2. Proceed to the "Diagnostic Overrides" screen on Cat ET. Activate the override for the starting system.

3. Measure the voltage between the wire from the SMMS and the engine ground.

4. Deactivate the override for the starting system.

5. Restore the wiring to the original configuration.

Expected Result:

The voltage measures 24 ± 3 VDC.

Results:

• OK - The voltage measures 24 ± 3 VDC. The problem appears to be in the starting motor solenoid.

  Repair: Verify that you have continuity on the return wire for the starting motor solenoid between terminal G and the −Battery. If the return wire for the starting motor solenoid is OK, verify that you have continuity on the +Battery wire for the starting motor solenoid between terminal +Batt and the +Battery. If the wires to the starting motor solenoid are OK, Install a new starting motor solenoid.

  STOP

• Not OK - The voltage does not measure 24 ± 3 VDC. The problem is in the wiring between the SMMS and the starting motor solenoid.

  Repair: Repair the wiring.

  STOP