3512B Generator Set Engine Caterpillar

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

Perform this procedure under conditions that are identical to the conditions that exist when the problem occurs. Typically, problems with the injector solenoid occur when the engine is warmed up and/or when the engine is under vibration (heavy loads).

These engines have Electronic Unit Injectors (EUI) that are mechanically actuated and electronically controlled. The ECM sends a 105 volt pulse to each injector solenoid. The pulse is sent at the proper time and at the correct duration for a given engine load and speed. The solenoid is mounted on top of the fuel injector body.

If an open is detected in the solenoid circuit, a diagnostic code is generated. The ECM continues to try to fire the injector. If a short is detected, a diagnostic code is generated. The ECM will disable the solenoid circuit. The ECM will periodically try to fire the injector. If the short circuit remains, this sequence of events will be repeated until the problem is corrected.

When an injector is replaced, program the new injector code into the ECM. If the ECM is replaced, all sixteen injector codes must be programmed into the new ECM. The injector codes are a four digit number. Refer to Troubleshooting, "Configuration Parameters" for information on injector codes.

Caterpillar Electronic Technician (ET) includes the following tests that aid in troubleshooting the injector solenoids:

"Cylinder Cutout Test"

All active diagnostic codes must be repaired before running the "Cylinder Cutout Test". Use the "Cylinder Cutout Test" to diagnose a malfunctioning injector while the engine is running. When a good injector is cut out, the "Delivered Fuel Volume" of the remaining injectors should change. The change in "Delivered Fuel Volume" is due to the extra load on each of the remaining cylinders. If a malfunctioning injector is cut out, the "Delivered Fuel Volume" will not change for the remaining injectors. The "Cylinder Cutout Test" is used to isolate the malfunctioning injector in order to avoid replacement of good injectors.

"Injector Solenoid Test"

Use the "Injector Solenoid Test" to aid in diagnosing an open circuit or a short circuit while the engine is not running. The "Injector Solenoid Test" briefly activates each solenoid. A good solenoid will create an audible click when the solenoid is activated. Cat ET will indicate the status of the solenoid as "OK", "Open", or "Short".

Illustration 1	g01626075
Typical schematic

Illustration 2	g01626076
P2 terminals that are associated with the injector solenoids (P2-1) Injector cylinder #1 power (P2-2) Injector cylinder #1 return (P2-3) Injector cylinder #2 power (P2-4) Injector cylinder #2 return (P2-40) Injector cylinder #3 power (P2-41) Injector cylinder #3 return (P2-42) Injector cylinder #4 power (P2-43) Injector cylinder #4 return (P2-14) Injector cylinder #5 power (P2-15) Injector cylinder #5 return (P2-16) Injector cylinder #6 power (P2-17) Injector cylinder #6 return (P2-48) Injector cylinder #7 power (P2-49) Injector cylinder #7 return (P2-50) Injector cylinder #8 power (P2-51) Injector cylinder #8 return (P2-24) Injector cylinder #9 power (P2-25) Injector cylinder #9 return (P2-34) Injector cylinder #10 power (P2-35) Injector cylinder #10 return (P2-58) Injector cylinder #11 power (P2-59) Injector cylinder #11 return (P2-52) Injector cylinder #12 power (P2-62) Injector cylinder #12 return

Illustration 3	g01626077
Terminal locations for the C-C1/E-C1/E-C2 Left hand cross over harness (Terminal BC) Injector cylinder #1 power (Terminal BM) Injector cylinder #1 return (Terminal BD) Injector cylinder #3 power (Terminal BN) Injector cylinder #3 return (Terminal BE) Injector cylinder #5 power (Terminal BP) Injector cylinder #5 return (Terminal BF) Injector cylinder #7 power (Terminal BR) Injector cylinder #7 return (Terminal BH) Injector cylinder #9 power (Terminal BS) Injector cylinder #9 return (Terminal BJ) Injector cylinder #11 power (Terminal BT) Injector cylinder #11 return

Illustration 4	g01622856
Connector locations (1) A-C1/E-C2/E-C1 Right hand cross over harness (2) A-C2/J-C2/J-C1 Right hand cross over harness (3) A-C90/P-C1 Connectors for the power distribution panel (4) A-C91/P-C2 Connectors for the power distribution panel (5) A-C60 Connector for the prelube motor (6) A-C92/F-C1/F-C2/G-C6 Connectors for a RH Control panel (7) C-C22 Primary ECM connector P2 (8) C-C15 Primary ECM connector P1 (9) C-C28 Secondary ECM connector P2 (10) C-C29 Secondary ECM connector P1 (11) C-C47 Connector for the power relay panel (12) C-C17/F-C1/F-C2/G-C6 Connectors for a LH Control panel (13) C-C18/(TB-C1 customer or L-C1/L-C2 EMCP 3) connectors (14) C-C2/J-C1/J-C2 Left hand cross over harness (15) C-C1/E-C1/E-C2 Left hand cross over harness

Test Step 1. Inspect Electrical Connectors and Wiring

1. Remove power from the ECM.

2. Thoroughly inspect the ECM connector J2/P2. Inspect the connectors for the injectors. Refer to the diagnostic functional test 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 allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.

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, 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 - 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 Logged Diagnostic Codes

1. Connect Cat ET to the service tool connector.

2. Restore power to the ECM.

3. Check for logged diagnostic codes for the injector solenoids on Cat ET.

Expected Result:

No 1-5 to 16-5 or 1-6 to 16-6 codes are logged.

Results:

• OK - No 1-5 to 16-5 or 1-6 to 16-6 codes are logged. Proceed to Test Step 3.

• Not OK - A 1-5 to 16-5 code is logged. Proceed to Test Step 4.

• Not OK - A 1-6 to 16-6 code is logged. Proceed to Test Step 5.

Test Step 3. Perform the "Cylinder Cutout Test"

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NOTICE
Engine power is reduced when a properly functioning cylinder is cut out. Make sure that you will not damage auxiliary or driven equipment if the engine power is suddenly reduced.

1. Remove power from the ECM.

2. Verify that the ECM connector J2/P2 and the injector connectors are properly connected.

3. Restore power to the ECM.

4. Start the engine.

5. Apply a load to the engine.

6. Perform the following steps on all suspect cylinders (solenoids).

7. Use the diagnostic tests on Cat ET to initiate the "Cylinder Cutout Test".

8. Perform the "Cylinder Cutout Test". Disable the suspect cylinder(s) during the test.

Expected Result:

The results indicated that the remaining injectors used more fuel when the "Cylinder Cutout Test" disabled the suspect injector(s).

Results:

• OK - There was a noticeable change in fuel usage.

  Repair: The injectors are firing in all cylinders. Reset the system and check for diagnostic codes.

  STOP

• Not OK - There was no noticeable change in fuel usage.

  Repair: Verify that the engine valve lash for that injector is set correctly. Rerun the "Cylinder Cutout Test". If the problem is still present, replace the injector. If the new injector has a trim code that is different from the old injector, change the trim code in the ECM.

  STOP

Test Step 4. Check the Harness between the ECM and the Injector Connectors for an Open Circuit

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This engine uses high voltage to control the fuel injectors. Disconnect electronic fuel injector enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running.

1. Remove power from the ECM.

2. Disconnect the connectors for the suspect injector(s).

3. Fabricate a jumper wire 100 mm (4 inch) long with Deutsch pins on both ends of the wire.

4. Insert one end of the jumper wire into the socket for the suspect injector's power wire. Insert the other end of the jumper wire into the socket for the suspect injector's return wire. This will replace the injector solenoid with a short circuit.

5. Restore power to the ECM.

   Note: This test will help the service technician verify that the ECM can fire the solenoids. Do not try to manually crank the engine during this test. The ECM will terminate the "Injector Solenoid Test".

6. Perform the "Injector Solenoid Test" at least two times.

7. Repeat this test for each suspect injector. Stop the "Injector Solenoid Test" before handling the jumper wire.

Expected Result:

Cat ET displays "Short" for the cylinder with the jumper wire.

Results:

• OK - Cat ET displays "Short" for the cylinder with the jumper wire. The harness between the ECM and the injector connector does not have an open circuit. Proceed to Test Step 9.

• Not OK - Cat ET displays "Open" for a right side cylinder with a jumper wire. There is a problem in the wiring between the ECM and the injector connector. Proceed to Test Step 7.

• Not OK - Cat ET displays "Open" for a left side cylinder with a jumper wire. There is a problem in the wiring between the ECM and the injector connector. Proceed to Test Step 8.

Test Step 5. Check the Harness between the ECM and the Connectors for the Injector for a Short Circuit

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This engine uses high voltage to control the fuel injectors. Disconnect electronic fuel injector enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running.

1. Remove power from the ECM. A strong electrical shock hazard is present if power is not removed from the ECM.

2. Disconnect the connectors for the suspect injector(s).

3. Restore power to the ECM.

   Note: This test will help the service technician verify that the ECM can fire the solenoids. Do not try to manually crank the engine during this test. The ECM will terminate the "Injector Solenoid Test".

4. Perform the "Injector Solenoid Test" at least two times.

Expected Result:

All of the suspect cylinders indicate "Open" on Cat ET.

Results:

• OK - All cylinders indicate "Open" on Cat ET. The harness between the ECM and the injector connector does not have a short circuit. Proceed to Test Step 9.

• Not OK - Cat ET displays "Short" for a right side cylinder. Note the cylinders that indicate "Short". Proceed to Test Step 6.

• Not OK - Cat ET displays "Short" for a left side cylinder. Note the cylinders that indicate "Short". Proceed to Test Step 8.

Test Step 6. Check the Harness between the ECM and the Rigid Harness for a Short Circuit

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This engine uses high voltage to control the fuel injectors. Disconnect electronic fuel injector enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running.

1. Remove power from the ECM. A strong electrical shock hazard is present if power is not removed from the ECM.

2. Disconnect the wires for the suspect injectors from the rigid harness. Refer to Illustration 3 for the terminal locations for the rigid harness.

3. Restore power to the ECM.

   Note: This test will help the service technician verify that the ECM can fire the solenoids. Do not try to manually crank the engine during this test. The ECM will terminate the "Injector Solenoid Test".

4. Perform the "Injector Solenoid Test" at least two times.

Expected Result:

All of the suspect cylinders indicate "Open" on Cat ET.

Results:

• OK - All cylinders indicate "Open" on Cat ET. The injector wires between the ECM and the rigid harness do not have a short circuit.

  Repair: The short circuit is in the harness between the rigid harness and the connector for the suspect injector. Repair the harness or the connector.

  STOP

• Not OK - One or more cylinders indicate "Short" on Cat ET. Note the cylinders that indicate "Short". Proceed to Test Step 8.

Test Step 7. Check the Harness between ECM and the Rigid Harness for an Open Circuit

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This engine uses high voltage to control the fuel injectors. Disconnect electronic fuel injector enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running.

1. Remove power from the ECM.

2. Disconnect the wires for the suspect injector from the rigid harness.

3. Fabricate a jumper wire with clips on both ends of the wire.

4. Install the wire jumper between the suspect injector's power wire and the suspect injector's return wire. This will replace the injector solenoid with a short circuit. Refer to Illustration 3 for the terminal locations for the rigid harness.

5. Restore power to the ECM.

   Note: This test will help the service technician verify that the ECM can fire the solenoids. Do not try to manually crank the engine during this test. The ECM will terminate the "Injector Solenoid Test".

6. Perform the "Injector Solenoid Test" at least two times.

7. Repeat this test for each suspect injector. Stop the "Injector Solenoid Test" before handling the jumper wire.

Expected Result:

Cat ET displays "Short" for the cylinder with the jumper wire.

Results:

• OK - Cat ET displays "Short" for the cylinder with the jumper wire. The harness between the rigid harness and the ECM does not have an open circuit.

  Repair: The open circuit is in the harness between the rigid harness and the connector for the suspect injector. Repair the harness or the connector.

  STOP

• Not OK - Cat ET displays "Open" for the cylinder with the jumper wire. There is a problem in the harness between the ECM and the rigid harness. Proceed to Test Step 8.

Test Step 8. Check the ECM for Proper Operation

1. Remove power from the ECM. A strong electrical shock hazard is present if power is not removed from the ECM.

2. Check the operation of the ECM by creating an open at the ECM.

   1. Disconnect the appropriate suspect injector wire from the P2 ECM connector. Remove the power wire for the suspect injector(s) from the ECM connector.

   2. Install a jumper wire with Deutsch sockets on each end into the socket for the power wire of the suspect injector(s).

   3. Reconnect the ECM connector.

   4. Restore power to the ECM.

      Note: This test will help the service technician verify that the ECM can fire the solenoids. Do not try to manually crank the engine during this test. The ECM will terminate the "Injector Solenoid Test".

   5. Perform the "Injector Solenoid Test".

   6. All of the suspect cylinders indicate "Open" on Cat ET.

   7. Remove power from the ECM.

3. Check the operation of the ECM by creating a short at the ECM.

   1. Create a short between the wire jumper for the suspect power wire and engine ground.

   2. Restore power to the ECM.

      Note: This test will help the service technician verify that the ECM can fire the solenoids. Do not try to manually crank the engine during this test. The ECM will terminate the "Injector Solenoid Test".

   3. Perform the "Injector Solenoid Test".

   4. Cat ET displays "Short" for the cylinder with the jumper wire.

   5. Remove power from the ECM.

   6. Remove the wire jumper. Reconnect all wires and connectors.

Expected Result:

Cat ET displays "Short" when the wire jumper is shorted to engine ground. Cat ET displays "Open" when the power wire for the injector is removed from the ECM connector.

Results:

• OK - The ECM is operating properly. The problem is between the ECM and the rigid harness for a right side cylinder or between the ECM and the connector for the injector for a left side cylinder.

  Repair: Repair the harness or the connector. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect". Verify that the repair eliminates the problem.

  STOP

• Not OK - The ECM did not detect the open or the short.

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

  STOP

Test Step 9. Measure the Resistance of the Injector Solenoid

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Personal injury can result from high voltage. The Electronic Control Module produces high voltage. Make sure the Electronic Control Module is not powered and the fuel injector solenoids are disconnected before proceeding.

1. Measure the solenoid resistance between pin 1 and pin 2 at the injector connector.

2. Record the measured resistance for each suspect solenoid.

Expected Result:

The resistance is 1.06 ± 0.5 Ohms.

Results:

• OK - The resistance is 1.06 ± 0.5 Ohms.

  Repair: The problem may be intermittent. If the problem is intermittent, refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect". Verify that the repair eliminates the problem.

  STOP

• Not OK - The resistance is not 1.06 ± 0.5 Ohms.

  Repair: Replace the injector. If the new injector has a trim code that is different from the old injector, change the trim code in the ECM.

  STOP