3524B Engines for Off-Highway Trucks Caterpillar

The engine has Electronic Fuel Injectors that are mechanically actuated and electronically energized. The Electronic Control Module (ECM) sends a 105 volt pulse to a solenoid that is mounted on top of the fuel injector body. The pulse is sent at the proper time and at the correct duration for a given engine load and speed. 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 of CID FMI 1-05 to 12-05 is generated. The ECM continues to try to fire the injector. If a short is detected, a diagnostic code of CID FMI 1-06 to 12-06 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.

Note: The circuit numbers for the front engine begin with the letter T. The circuit numbers for the rear engine begin with the letter R.

Illustration 1	g00785081
Typical schematic

Illustration 2	g00785113
Typical schematic

Test Step 1. Check for Connector Damage.

1. Turn the circuit breaker for the battery to the OFF position.

2. Turn the keyswitch to the OFF position.

3. Disconnect the main power.

4. 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.

5. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.

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

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

8. 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 should be free of corrosion, of abrasion or of pinch points.

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. Check for "Active" Diagnostic Codes.

1. Turn the keyswitch to the OFF position.

2. Connect the Caterpillar Electronic Technician (ET) at the service tool connector.

3. Turn the keyswitch to the ON position. The engine should be OFF.

4. Observe the diagnostic display screen on the Cat ET.

Expected Result:

A CID-FMI 1-05 to 12-05 or 1-06 to 12-06 should not be active.

Results:

• OK - There are no active diagnostic codes on the Cat ET. Proceed to Test Step 3.

• Not OK - An active diagnostic code is present on the Cat ET. Proceed to Test Step 4.

Test Step 3. Perform the Injector Solenoid Test.

Note: The test verifies that the ECM can fire the solenoids. Do not try to crank the engine during this test. The engine will start and the ECM will terminate the Injector Solenoid Test.

1. Connect the Cat ET at the service tool connector.

2. Turn the keyswitch to the ON position. The engine should be OFF.

3. Use the diagnostic tests on the Cat ET to initiate the Injector Solenoid Test.

4. Listen for a click at each valve cover. A black square will appear over the cylinder number when the cylinder is being fired.

5. Repeat the test a few times. Verify that the ECM is energizing each solenoid.

Expected Result:

As each solenoid is energized by the ECM, an audible click of the solenoid should be heard. The solenoids will be energized one at a time in the following numerical order: 1-12. There will be momentary delay between each one.

Results:

• OK - An audible click of the solenoid was heard for each solenoid. Proceed to Test Step 5.

• Not OK - An audible click of the solenoid was not heard for each solenoid. Proceed to Test Step 4.

Test Step 4. Check for an Open Circuit in the Wiring Harness.

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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. Turn the keyswitch to the OFF position.

2. Disconnect the ECM connector J2/P2.

   Note: The circuit numbers for the front engine begin with the letter T. The circuit numbers for the rear engine begin with the letter R.

3. Measure the resistance between the solenoid wire pairs at the ECM connector P2.

   Measure the resistance for SOLENOID 1 at P2-16 and P2-5.

   Measure the resistance for SOLENOID 2 at P2-40 and P2-11.

   Measure the resistance for SOLENOID 3 at P2-26 and P2-5.

   Measure the resistance for SOLENOID 4 at P2-34 and P2-11.

   Measure the resistance for SOLENOID 5 at P2-32 and P2-17.

   Measure the resistance for SOLENOID 6 at P2-28 and P2-21.

   Measure the resistance for SOLENOID 7 at P2-38 and P2-17.

   Measure the resistance for SOLENOID 8 at P2-22 and P2-21.

   Measure the resistance for SOLENOID 9 at P2-37 and P2-27.

   Measure the resistance for SOLENOID 10 at P2-18 and P2-33.

   Measure the resistance for SOLENOID 11 at P2-31 and P2-27.

   Measure the resistance for SOLENOID 12 at P2-12 and P2-33.

Expected Result:

The resistance should be between 0.6 and 3.6 Ohms for each measurement.

Results:

• OK - The resistance is between 0.6 and 3.6 Ohms for each measurement. Proceed to Test Step 6.

• Not OK - The resistance is greater than 3.6 Ohms. There is an open in the harness or in an injector solenoid. Proceed to Test Step 7.

Test Step 5. Perform the Cylinder Cutout Test.

Note: This test will help the Service Technician verify a fuel delivery or a starvation problem when no diagnostic code is present.

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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 changes suddenly.

1. Connect the Cat ET at the service tool connector.

2. Start the engine. Apply a constant load to the engine.

3. Use the Cat ET to cut out a single solenoid by using the Cylinder Cutout Test.

4. Check for a difference in the sound, feel, or power of the engine as each cylinder is cut out. The amount of change should be similar for all of the good cylinders. The amount of change should be minimal for a weak cylinder or for a bad cylinder.

5. Disable the override. Repeat this step for each of the solenoids.

Expected Result:

The amount of change should be similar for all of the good cylinders. The amount of change should be minimal for a weak cylinder or for a bad cylinder.

Results:

• OK - There was a noticeable change in engine performance during the Cylinder Cutout Test.

  STOP

• Not OK - There was no noticeable change in engine performance during the Cylinder Cutout Test.

  Repair: Remove the valve cover and check the injector and valve lash setting for damage or misadjustment. If no repair is required, replace the injector. Refer to Specifications, "Fuel Injector" for the proper torques.

  STOP

Test Step 6. Check for a Short Circuit in the Wiring Harness.

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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. Disconnect the injector connectors J4 through J15 for the injector solenoids.

   Note: The circuit numbers for the front engine begin with the letter T. The circuit numbers for the rear engine begin with the letter R.

2. Measure the resistance between the solenoid wire pairs from ECM connector P2.

   Measure the resistance for SOLENOID 1 at P2-16 and P2-5.

   Measure the resistance for SOLENOID 2 at P2-40 and P2-11.

   Measure the resistance for SOLENOID 3 at P2-26 and P2-5.

   Measure the resistance for SOLENOID 4 at P2-34 and P2-11.

   Measure the resistance for SOLENOID 5 at P2-32 and P2-17.

   Measure the resistance for SOLENOID 6 at P2-28 and P2-21.

   Measure the resistance for SOLENOID 7 at P2-38 and P2-17.

   Measure the resistance for SOLENOID 8 at P2-22 and P2-21.

   Measure the resistance for SOLENOID 9 at P2-37 and P2-27.

   Measure the resistance for SOLENOID 10 at P2-18 and P2-33.

   Measure the resistance for SOLENOID 11 at P2-31 and P2-27.

   Measure the resistance for SOLENOID 12 at P2-12 and P2-33.

3. Reconnect all connectors.

Expected Result:

The resistance should be greater than 20,000 Ohms for each measurement.

Results:

• OK - The resistance is greater than 20,000 Ohms for each measurement. Proceed to Test Step 8.

• Not OK - The resistance is less than 20,000 Ohms for each measurement. There is a short in the harness or connectors.

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

  STOP

Test Step 7. Isolate the Circuit.

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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. Disconnect the suspect solenoid at the valve cover base.

2. Measure the resistance of the solenoid at the valve cover base.

Expected Result:

The resistance should be between 0.6 and 3.6 Ohms for each measurement.

Results:

• OK - The resistance is between 0.6 and 3.6 Ohms for each measurement. There is an open circuit or excessive resistance in the harness or connectors between the ECM and the injector connector.

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

  STOP

• Not OK - The resistance is more than 3.6 Ohms. There is an open circuit under the valve cover base. Proceed to Test Step 9.

Test Step 8. Check the Resistance of the Solenoid at the Valve Cover Base.

1. Turn the keyswitch to the OFF position.

2. Disconnect the ECM connector J2/P2. Disconnect the solenoid connectors J4/P4 through J15/P15.

3. Measure the solenoid resistance between pin-1 and pin-2 at the solenoid connectors.

4. Record the measured resistance on each pair of pins.

Expected Result:

The resistance should be between 0.6 and 3.6 Ohms for each measurement.

Results:

• OK - The resistance is between 0.6 and 3.6 Ohms for each measurement. Reconnect the ECM connector P2. Reconnect the solenoid connectors. Repeat the Injector Solenoid Test. If the problem still exists, the ECM has a faulty injector driver.

  Repair: Replace the ECM. Refer to the diagnostic procedure Troubleshooting, "Replacing the ECM" BEFORE replacing the ECM.

  STOP

• Not OK - The measured resistance is more than 3.6 Ohms, or less than 0.6 Ohms. There is a problem with the valve cover harness or the solenoid. Proceed to Test Step 9.

Test Step 9. Check the Resistance of the Solenoid at the Solenoid.

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

1. Turn the keyswitch to the OFF position.

2. Remove the valve cover of the suspect cylinder.

3. Remove the harness yoke from the solenoid terminals.

4. Measure the resistance between the two solenoid terminals on top of the suspect injector. Record the resistance.

5. Measure the resistance from either solenoid terminal to the injector. Record the resistance.

Expected Result:

Resistance between solenoid terminals should be between 0.6 and 3.6 Ohms. The normal resistance is 2.1 Ohms. The resistance from either solenoid terminal to the fuel injector body should be greater than 20,000 Ohms.

Results:

• OK - The solenoid is electrically okay but there is a problem in the valve cover base harness.

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

  STOP

• Not OK - The solenoid has failed.

  Repair: Replace the faulty injector. Refer to Specifications, "Fuel Injector" for the proper torques. Reconnect the harness yoke to the solenoid terminals. Recheck solenoid resistance at valve cover base. Verify that the harness is not damaged.

  STOP