Use this procedure for the following conditions:
- An injector solenoid may be inoperative or an injector solenoid may be operating erratically.
- You have been directed to this procedure from Troubleshooting, "Troubleshooting without a Diagnostic Code".
- There is an active diagnostic code for an injector solenoid.
Use this procedure for the following diagnostic codes:
- 1-03 Injector Cylinder 1 open circuit
- 1-04 Injector Cylinder 1 short
- 2-03 Injector Cylinder 2 open circuit
- 2-04 Injector Cylinder 2 short
- 3-03 Injector Cylinder 3 open circuit
- 3-04 Injector Cylinder 3 short
- 4-03 Injector Cylinder 4 open circuit
- 4-04 Injector Cylinder 4 short
- 5-03 Injector Cylinder 5 open circuit
- 5-04 Injector Cylinder 5 short
- 6-03 Injector Cylinder 6 open circuit
- 6-04 Injector Cylinder 6 short
- 7-03 Injector Cylinder 7 open circuit
- 7-04 Injector Cylinder 7 short
- 8-03 Injector Cylinder 8 open circuit
- 8-04 Injector Cylinder 8 short
- 9-03 Injector Cylinder 9 open circuit
- 9-04 Injector Cylinder 9 short
- 10-03 Injector Cylinder 10 open circuit
- 10-04 Injector Cylinder 10 short
- 11-03 Injector Cylinder 11 open circuit
- 11-04 Injector Cylinder 11 short
- 12-03 Injector Cylinder 12 open circuit
- 12-04 Injector Cylinder 12 short
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 hydraulically actuated and electronically controlled. The Engine Control Module (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.
Note: Refer to Illustration 1. Two injector solenoids share a common return wire. For this reason, an open circuit or a short circuit in a return wire could cause diagnostic codes for two injector solenoids.
The 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 "Fuel Position" should change. The change in the fuel position is caused by the other injectors that are compensating for the cut out injector. If a malfunctioning injector is cut out, the "Fuel Position" will not change. 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".
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| Illustration 1 | g01137557 |
Schematic for injector solenoids | |
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The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere. |
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Test Step 1. Inspect the Electrical Connectors and the Wiring
- Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the ignition key is not turned off.
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Electrical shock hazard. The electronic unit injector system uses 90-120 volts. |
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- Thoroughly inspect connector (1). Also inspect injector connector (2) through injector connector (7). Refer to Troubleshooting, "Electrical Connectors - Inspect".
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| Illustration 2 | g01137664 |
Connector locations for injector solenoids (1) J2/P2 ECM connectors (2) J56/P56 Injector connectors (cylinders 2 & 4) (3) J57/P57 Injector connectors (cylinders 6 & 8) (4) J58/P58 Injector connectors (cylinders 10 & 12) (5) J52/P52 Injector connectors (cylinders 1 & 3) (6) J53/P53 Injector connectors (cylinders 5 & 7) (7) J54/P54 Injector connectors (cylinders 9 & 11) | |
- Perform a 45 N (10 lb) pull test on each of the wires for each injector on the engine.
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| Illustration 3 | g01137657 |
P2 ECM connector (P2-5) Injector 1 & 3 return (P2-11) Injector 2 & 4 return (P2-12) Injector 12 supply (P2-16) Injector 1 supply (P2-17) Injector 5 & 7 return (P2-18) Injector 10 supply (P2-21) Injector 6 & 8 return (P2-22) Injector 8 supply (P2-26) Injector 3 supply (P2-27) Injector 9 & 11 return (P2-28) Injector 6 supply (P2-31) Injector 11 supply (P2-32) Injector 5 supply (P2-33) Injector 10 & 12 return (P2-34) Injector 4 supply (P2-37) Injector 9 supply (P2-38) Injector 7 supply (P2-40) Injector 2 supply | |
- Check the harness and wiring for abrasion and for pinch points from the injectors to the ECM.
- Check the torque of the allen head screw for the ECM connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Expected Result:
All of the 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 harness and connectors appear to be in good repair. Proceed to Test Step 2.
- Not OK -
Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. 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
- Connect Cat ET to the service tool connector.
- Turn the keyswitch to the ON position.
- Check for logged diagnostic codes on Cat ET.
Expected Result:
The following diagnostic codes are not logged:
- 1-05 through 12-05
- 1-06 through 12-06
Results:
- OK - None of the diagnostic codes are logged. Proceed to Test Step 3.
- Not OK - One or more of the diagnostic codes are logged. Proceed to Test Step 4.
Test Step 3. Perform the Injector Solenoid Test
Note: This test will verify that the ECM can activate the injector solenoids. Do not try to crank the engine during this test. If the keyswitch is moved to the START position during the test, Cat ET will terminate the test.
- Turn the keyswitch to the ON position.
- Perform the injector solenoid test on Cat ET.
Note: Each solenoid is energized by the ECM one at a time in numerical order from 1 through 12. An audible click of the solenoid can be heard at the valve mechanism cover. There is a momentary delay between the activation of each injector solenoid.
- Listen for a click at each valve mechanism cover. Ensure that each injector solenoid is actuating during the test.
Note: Repeat the injector solenoid test a few times in order to verify that the ECM is energizing each solenoid.
Expected Result:
All of the solenoids are being energized by the ECM. An audible click of the solenoid is heard for each of the injector solenoids.
Results:
- OK - An audible click was heard for all of the injector solenoids. The solenoids appear to be operating correctly. Proceed to Test Step 9.
- Not OK - There was no audible click that was heard from one or more of the solenoids. There may be a problem with the injector solenoids or with the injector wiring. Proceed to Test Step 4.
Test Step 4. Check the Resistance at the ECM Connector
- Turn the keyswitch to the OFF position.
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Electrical shock hazard. The electronic unit injector system uses 90-120 volts. |
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- Disconnect the J2/P2 ECM connector.
- Measure the resistance at the P2 ECM connector between the solenoid supply and the solenoid return for each suspect solenoid. Refer to Illustration 3.
Expected Result:
The resistance is less than ten Ohms for the solenoid circuit.
Results:
- OK - The resistance for the solenoid circuits measures less than ten Ohms. There is not an open circuit in the harness or in the injector solenoid. Proceed to Test Step 5.
- Not OK - There is an open in the harness or there is an open in the injector solenoid. Proceed to Test Step 6.
Test Step 5. Check the Injector Harness for Shorts
- Disconnect the injector connector for the suspect solenoid at the valve cover base.
- Measure the resistance at the P2 ECM connector between the solenoid supply and the solenoid return for the suspect injector solenoid. Refer to Illustration 3.
Expected Result:
An open circuit is indicated for the solenoid circuit.
Results:
- OK - There are no shorts in the harness or the connectors. Proceed to Test Step 7.
- Not OK - There is a short in the harness, or there is excessive resistance in one of the connectors.
Repair: There may be a problem with the harness or with a connector. Inspect the connectors for moisture and for corrosion. Repair the wiring and/or the connector, when possible. Replace parts, if necessary. Verify that the problem is resolved.
STOP
Test Step 6. Isolate the Open Circuit
- Turn the keyswitch to the OFF position.
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Electrical shock hazard. The electronic unit injector system uses 90-120 volts. |
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- Disconnect the connector of the suspect injector at the valve cover base.
- Measure the solenoid resistance of the suspect injector at the valve cover base.
Expected Result:
Resistance is less than four Ohms.
Results:
- OK - There is an open circuit or excessive resistance between the terminals at the valve cover base.
Repair: The problem is with the harness or with the connectors that are between the ECM and the connector that is at the valve cover base. Repair the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect". Verify that the repair eliminates the problem.
STOP
- Not OK - There is an open circuit in the harness under the valve cover or in the injector solenoid. Proceed to Test Step 8.
Test Step 7. Measure Solenoid Resistance at Valve Cover Base
- Turn the keyswitch to the OFF position.
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Electrical shock hazard. The electronic unit injector system uses 90-120 volts. |
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- Ensure that the J2/P2 ECM connector and all of the unit injector connectors are disconnected.
- Measure the solenoid resistance between terminals 1 and 2 and between terminals 3 and 4 at the unit injector connectors. Record the measured resistance for each solenoid.
Expected Result:
Resistance is between 0.6 and 3.6 Ohms for each solenoid.
Results:
- OK -
Repair: Reconnect all connectors and repeat the injector solenoid test.If the problem still exists, the ECM may have a faulty injector driver. Replace the ECM. Refer to Troubleshooting, "Replacing the ECM".
STOP
- Not OK - There is a problem with the harness that is under the valve cover or with the injector solenoid. Proceed to Test Step 8.
Test Step 8. Check Resistance of the Injector Solenoid
- Turn the keyswitch to the OFF position.
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Electrical shock hazard. The electronic unit injector system uses 90-120 volts. |
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- Remove the valve mechanism cover for the suspect solenoid.
- Remove the harness connector from the solenoid terminals.
- Measure the resistance between the two solenoid terminals on top of the unit injector. Record this resistance.
- Measure the resistance from either solenoid terminal to the unit injector body (metal). Record this resistance.
Expected Result:
The resistance between the two solenoid terminals is between 0.6 and 3.6 Ohms and an open circuit is indicated between the injector terminals and the body of the injector.
Results:
- OK - The injector solenoid is electrically OK. There is a problem in the valve cover base harness.
Repair: Repair the injector harness, when possible. Replace parts, if necessary. Verify that the repair eliminates the problem.
STOP
- Not OK - The injector solenoid has failed.
Repair: Replace the injector. Refer to Disassembly and Assembly, "Unit Injector - Remove". Verify that the repair eliminates the problem.
STOP
Test Step 9. Perform the Cylinder Cutout Test
- Turn the keyswitch to the OFF/RESET position.
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Electrical shock hazard. The electronic unit injector system uses 90-120 volts. |
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| NOTICE |
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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. |
- Verify that the J2/P2 ECM connector and the J52/P52 through J58/P58 unit injector connectors are properly connected.
- Turn the keyswitch to the ON position.
- Start the engine.
- When possible, apply a load to the engine. This will help to differentiate a weak cylinder or a cold cylinder.
- Perform the cylinder cutout test on Cat ET.
- 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 cold cylinder.
- Disable the override. Repeat above steps for each cylinder (solenoid).
Expected Result:
The cylinder cutout test indicates that all of the injectors are operating correctly.
Results:
- OK - The cylinder cutout test indicates that all of the injectors are operating correctly.
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".
STOP
- Not OK - A cylinder is malfunctioning. This indicates that there is a problem with an injector.
Repair: Replace the injector. Refer to the Disassembly and Assembly for the correct procedure. Verify that the repair eliminates the problem.
STOP