3406E, C-10, C-12, C-15, C-16 and C-18 On-highway Engines Caterpillar

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).

The following background information is related to this procedure:

These engines have Electronic Unit Injectors that are mechanically actuated and electronically energized. The engine control module 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. The 105 volt pulse can be individually cut out to aid in troubleshooting misfire problems.

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 then enable the solenoid. If the short circuit remains this sequence of events will be repeated until the problem is corrected.

Some personality modules require the injector codes to be programmed. Injector codes allow each individual injector to be fine tuned for optimum performance. The ECM will generate the following diagnostic code if the injector codes are not programmed:

• 253-02 Check Customer or System Parameters

When an injector is replaced, program the injector code that is etched on the injector. The injector code is a four digit number. If the ECM is replaced, all six injector codes must be programmed into the new ECM. Refer to Troubleshooting, "Injector Code - Calibrate".

Illustration 1	g00735975
Electronic Unit Injector

Illustration 2	g06412820
Schematic for electronic unit injector

Illustration 3	g00663571
P2 ECM connector

Test Step 1. INSPECT ELECTRICAL CONNECTORS AND WIRING

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.

2. Thoroughly inspect the ECM engine harness connector J2/P2 and the solenoid connector for the Injector J300/P300. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

3. Perform a 45 N (10 lb) pull test on each of the wires in the J2/P2 ECM connector and the J300/P300 valve cover connector that are associated with injector solenoids.

   Refer to Illustration 3.

4. Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).

5. Check the J300/P300 valve cover connector in order to ensure the proper mating of the connector.

6. Check the harness and wiring for abrasion and pinch points from the injectors to the ECM.

Expected Result:

All connectors, pins, and sockets should be completely coupled and/or inserted and the harness and wiring should be free of corrosion, abrasion, or pinch points.

Results:

• OK - Proceed to Test Step 2.

• Not OK -

  Repair: Perform the following 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 REGARDING INJECTOR SOLENOIDS

1. Connect the Caterpillar Electronic Technician (ET) to the data link connector.

2. Turn the key switch to the ON position.

3. Monitor the logged diagnostic code screen on Cat ET.

Expected Result:

One or more diagnostic codes for the injectors have been logged:

Results:

• OK - Proceed to Test Step 4.

• Not OK - Proceed to Test Step 3.

Test Step 3. CHECK THE VARIATION OF THE INJECTORS FROM A CYLINDER TO A CYLINDER

Illustration 4	g00663575
"Automated Cylinder Cutout Test" screen in Caterpillar Electronic Technician (Cat ET)

1. Connect Cat ET to the data link connector.

2. When possible, put the truck on a dynamometer.

3. Start the engine.

4. Allow the engine to warm up to normal operating temperature 77 °C (171 °F).

5. After the engine is warmed to operating temperature, access the "Cylinder Cutout Test" by accessing the following display screens in order:

   • "Diagnostics"

   • "Diagnostic Tests"

   • "Cylinder Cutout Test"

6. Enable the cooling fan, if the fan is not controlled by the ECM. If the ECM controls the cooling fan, the cooling fan will start automatically when the test begins.

7. Shut off all parasitic loads such as the air conditioning and the air compressors which could affect the results of the test.

8. Set the engine speed to 1000 ± 20 rpm.

9. Select the start button at the bottom of the screen for the "Cylinder Cutout Test".

10. Select the "4 Cylinder Cutout Test" which is the default test.

11. Follow the instructions that are provided in the Cylinder Cutout Test. The Cylinder Cutout Test is interactive so the procedure is guided to the finish.

    Note: The "Manual Cylinder Cutout Test" is also available. Access the manual test by selecting the "Change" button on the Cat ET screen for the Cylinder Cutout Test. The "4 Cylinder Cutout Test" is the recommended starting procedure. The automated tests run twice collecting data. The two sets of data are analyzed and an "OK" or "NOT OK" result is displayed.

Expected Result:

All cylinders indicate "OK" on Cat ET.

Results:

• OK -

  Repair: If the engine is misfiring or if the engine has low power, refer to Troubleshooting, "Engine Misfires, Runs Rough or Is Unstable" and Troubleshooting, "Low Power/Poor or No Response to Throttle".

  If a diagnostic code results from running the Cylinder Cutout Test, proceed to Test Step 4.

• Not OK - Proceed to Test Step 4.

Test Step 4. USE THE INJECTOR SOLENOID TEST TO TEST THE INJECTOR SOLENOIDS

Illustration 5	g00663576
"Injector Solenoid Test" screen in Caterpillar Electronic Technician (Cat ET)

1. Start the engine.

2. Allow the engine to warm up to 77 °C (171 °F) which is the normal operating temperature.

3. Turn the key switch to the OFF position.

4. Connect Cat ET to the data link connector.

5. Turn the key switch to the ON position.

6. After the engine is warmed to operating temperature, access the "Injector Solenoid Test" by accessing the following display screens in order:

   • "Diagnostics"

   • "Diagnostic Tests"

   • "Injector Solenoid Test"

7. Activate the test.

   Note: Do not confuse the Injector Solenoid Test with the Cylinder Cutout Test. The Cylinder Cutout Test is used to shut off fuel to a specific cylinder while the engine is running. The Injector Solenoid Test is used in order to actuate the injector solenoids. This allows the click of the injector solenoids to be heard when the engine is not running in order to determine that the circuit is functioning properly.

8. As each solenoid is energized by the ECM an audible click can be heard at the valve cover. Listen for a click at each valve cover. A black square will appear over the cylinder number when the cylinder is being fired.

9. Perform the Injector Solenoid Test at least two times.

Expected Result:

All cylinders indicate "OK".

Results:

• OK - There is not an electronic problem with the injectors at this time.

  Repair: If the Cylinder Cutout Test returned a "NOT OK" for any injector, refer to Troubleshooting, "Engine Misfires, Runs Rough or Is Unstable".

  STOP

• Not OK - Note the cylinders that indicate "OPEN" and/or "SHORT". Proceed to Test Step 5.

Test Step 5. USE THE INJECTOR SOLENOID TEST TO CHECK THE ENGINE HARNESS FROM P2 TO P300 FOR SHORT CIRCUITS

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.

2. Disconnect the J300/P300 injector connector.

3. Turn the key switch to the ON position.

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

Expected Result:

All cylinders indicate "OPEN".

Results:

• OK - Proceed to Test Step 6.

• Not OK - Note the cylinders that indicate a short circuit. Proceed to Test Step 7.

Test Step 6. USE THE INJECTOR SOLENOID TEST TO CHECK THE ENGINE HARNESS FROM P2 TO P300 FOR AN OPEN CIRCUIT

Illustration 6	g00663572
Injector connector for Engine harness

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.

2. Disconnect injector connector J300/P300.

3. Turn the key switch to the ON position.

4. Fabricate a jumper wire 100 mm (4 inch) long. Crimp a Deutsch pin to both ends of the wire.

5. Insert one end of the jumper wire into the "Injector Common" socket of the problem injector. Insert the other end of the jumper wire into the socket of injector connector P300 that goes to the problem injector. For example, if Injector 5 is the problem injector, insert the jumper from terminal 5 of the injector connector P300 to terminal 8 of the injector connector P300.

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

7. Repeat this test for each suspect Injector. Ensure that the Injector Solenoid Test is disabled before handling the jumper wires.

Expected Result:

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

Results:

• OK - Proceed to Test Step 8.

• Not OK - Proceed to Test Step 9.

Test Step 7. USE THE INJECTOR SOLENOID TEST TO CHECK THE ECM FOR SHORT CIRCUITS

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.

2. Disconnect the J2/P2 ECM connector from the ECM and check for evidence of moisture entry.

3. Turn the key switch to the ON position.

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

Expected Result:

All cylinders indicate "OPEN" when the P2 ECM connector is disconnected from the ECM.

Note: When the engine harness is disconnected all of the diagnostic codes for supply voltage to the sensors will be active. This is normal. Clear all of these diagnostic codes after completing this test step.

Results:

• OK - The short circuit is in the engine harness.

  Repair: Perform the following repair:

  Repair the engine harness or replace the engine harness, as required. Clear all diagnostic codes after completing this test step.

  Verify that the repair eliminates the problem.

  STOP

• Not OK -

  Repair: Perform the following repair:

  1. Temporarily connect a test ECM.

  2. Remove all jumpers and replace all connectors.

  3. Recheck the system for active diagnostic codes.

  4. Repeat the Test Step.

  5. If the problem is resolved with the test ECM, reconnect the suspect ECM.

  6. If the problem returns with the suspect ECM, replace the ECM.

  7. Verify that the repair eliminates the problem.

  STOP

Test Step 8. EVALUATE THE SYMPTOMS

Expected Result:

Choose from these possible results:

Result 1 Test Step 6 indicated that only one injector had an "OPEN" or "SHORT", or that one injector had an "OPEN" but the other injector on the injector common line had a "SHORT".

Result 2 Test Step 6 indicated that two injectors that share an injector common line are open.

Result 3 Test Step 6 indicated that two injectors that share an injector common line are shorted.

Results:

• Result 1 - Proceed to Test Step 10.

• Result 2 - Proceed to Test Step 11.

• Result 3 - Proceed to Test Step 12.

Test Step 9. CHECK THE ECM FOR AN OPEN CIRCUIT

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.

2. Disconnect the J2/P2 ECM connector. Connect a 140-2266 Cable (Seventy-Pin Breakout) to the ECM. Do not connect the engine harness to the breakout T.

3. Use a jumper wire to short between the socket of the injector and the common socket of the suspect injector.

4. Turn the key switch to the ON position.

5. Perform the Injector Solenoid Test at least two times.

Expected Result:

ET displays "SHORT" for the cylinder with the jumper wire.

Note: When the engine harness is disconnected all of the diagnostic codes for supply voltage to the sensors will be active. This is normal. Clear all of these diagnostic codes after completing this test step.

Results:

• OK - The ECM is OK.

  Repair: Perform the following repair:

  Replace the engine harness or repair the engine harness, as required.

  Verify that the repair eliminates the problem.

  STOP

• Not OK -

  Repair: Perform the following repair:

  1. Temporarily connect a test ECM.

  2. Remove all jumpers and replace all connectors.

  3. Recheck the system for active diagnostic codes.

  4. Repeat the Test Step.

  5. If the problem is resolved with the test ECM, reconnect the suspect ECM.

  6. If the problem returns with the suspect ECM, replace the ECM.

  7. Verify that the repair eliminates the problem.

  STOP

Test Step 10. CHECK THE INJECTOR HARNESS UNDER THE VALVE COVER

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.

2. Remove the valve cover.

3. Disconnect the harness from the problem injector. Disconnect the harness from the other injector that has the same injector common line.

4. Thoroughly clean the terminals of both injectors and the harness.

5. Exchange the harness between the two injectors that share the common line.

6. Turn the key switch to the ON position.

7. Perform the Injector Solenoid Test at least two times.

Expected Result:

Exchanging the harness between the two injectors caused the problem to move to the other injector on Cat ET.

Results:

• OK -

  Repair: Perform the following repair:

  Replace the faulty injector. Restore the wiring to the proper injectors.

  Verify that the repair eliminates the problem.

  STOP

• Not OK -

  Repair: Perform the following repair:

  Replace the injector harness under the valve cover.

  Verify that the repair eliminates the problem.

  STOP

Test Step 11. CHECK THE ENGINE HARNESS UNDER THE VALVE COVER FOR AN OPEN CIRCUIT IN THE COMMON LINE

Illustration 7	g00663574
Harness terminals of Electronic Unit Injector

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.

2. Remove the valve cover.

3. Disconnect each of the injectors that indicate an "OPEN" from the wiring harness. Ensure that each of the connectors from the disconnected injector harness does not touch other components and short to ground.

4. Attach a jumper wire to both terminals of the injector harness for the two injectors that share an injector common line.

5. Turn the key switch to the ON position.

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

Expected Result:

The cylinders with the short in place indicate an "OPEN".

Results:

• OK -

  Repair: Perform the following repair:

  1. Replace the engine harness under the valve cover.

  2. Use the Injector Solenoid Test to check the installation of the new harness before installing the valve covers.

  3. Verify that the repair eliminates the problem.

  STOP

• Not OK - Both injectors indicate "SHORT".

  Repair: Perform the following repair:

  Both injectors indicate "SHORT". Replace Both injectors.

  Verify that the repair eliminates the problem.

  STOP

Test Step 12. CHECK THE ENGINE HARNESS UNDER THE VALVE COVER FOR SHORT CIRCUITS IN THE INJECTOR WIRES

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.

2. Remove the valve cover.

3. Disconnect each of the injectors that indicate a "SHORT" from the wiring harness. Ensure that each of the connectors from the disconnected injector harness does not touch other components and short to ground.

4. Turn the key switch to the ON position.

5. Perform the Injector Solenoid Test at least two times.

Expected Result:

Both cylinders indicate an "OPEN".

Results:

• OK - Leave the injector wires disconnected. Neither of the injector wires are shorted to the engine. Proceed to Test Step 13.

• Not OK -

  Repair: Perform the following repair:

  Replace the injector harness under the valve cover.

  Verify that the repair eliminates the problem.

  STOP

Test Step 13. CHECK FOR A SHORT CIRCUIT IN THE INJECTOR COMMON LINE TO THE ENGINE

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.

2. Disconnect the J2/P2 ECM connector.

3. Locate the common line for the problem injector in the P2 connector. Measure the resistance from the terminal to the engine ground stud connection.

Expected Result:

The multimeter indicates that the resistance is greater than 10 Ohms.

Results:

• OK - Reconnect the engine harness to the ECM. Proceed to Test Step 14.

• Not OK -

  Repair: Perform the following repair:

  Replace the injector harness under the valve cover.

  Verify that the repair eliminates the problem.

  STOP

Test Step 14. CHECK FOR A SHORT CIRCUIT IN THE INJECTOR

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.

2. Reconnect one of the two disconnected injectors.

3. Turn the key switch to the ON position.

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

Expected Result:

The reconnected injector indicates a "SHORT".

Results:

• OK -

  Repair: Perform the following repair:

  Replace the Injector.

  Verify that the repair eliminates the problem.

  STOP

• Not OK - The injector is OK. Proceed to Test Step 15.

Test Step 15. CHECK FOR A SHORT CIRCUIT IN THE OTHER INJECTOR

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the key switch to the OFF position. A strong electrical shock hazard is present if the key switch is not turned off.

2. Reconnect the other disconnected injector.

3. Turn the key switch to the ON position.

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

Expected Result:

The reconnected injector indicates a "SHORT".

Results:

• OK -

  Repair: Perform the following repair:

  Replace the faulty injector. Restore the wiring to the proper injectors.

  Verify that the repair eliminates the problem.

  STOP

• Not OK - This injector is OK.

  STOP