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.
| Diagnostic Codes Table | ||
|---|---|---|
| Code | Conditions which Generate this Code | System Response |
| 1-5 Cylinder #1 Injector : Current Below Normal | The engine's Electronic Control Module (ECM) detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 1-6 Cylinder #1 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 2-5 Cylinder #2 Injector : Current Below Normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 2-6 Cylinder #2 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 3-5 Cylinder #3 Injector : Current Below Normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 3-6 Cylinder #3 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 4-5 Cylinder #4 Injector : Current Below Normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 4-6 Cylinder #4 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 5-5 Cylinder #5 Injector : Current Below Normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 5-6 Cylinder #5 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 6-5 Cylinder #6 Injector : Current Below Normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 6-6 Cylinder #6 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 7-5 Cylinder #7 Injector : Current Below Normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 7-6 Cylinder #7 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 8-5 Cylinder #8 Injector : Current Below Normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 8-6 Cylinder #8 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 9-5 Cylinder #9 Injector : Current Below Normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 9-6 Cylinder #9 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 10-5 Cylinder #10 Injector : Current Below Normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 10-6 Cylinder #10 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 11-5 Cylinder #11 Injector : Current Below Normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 11-6 Cylinder #11 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 12-5 Cylinder #12 Injector : Current Below Normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 12-6 Cylinder #12 Injector : Current Above Normal | The ECM detects a short circuit. | The code is logged. 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. |
| 13-5 Cylinder #13 Injector current below normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 13-6 Cylinder #13 Injector current above normal | The ECM detects a short circuit. | The code is logged. 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. |
| 14-5 Cylinder #14 Injector current below normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 14-6 Cylinder #14 Injector current above normal | The ECM detects a short circuit. | The code is logged. 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. |
| 15-5 Cylinder #15 Injector current below normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 15-6 Cylinder #15 Injector current above normal | The ECM detects a short circuit. | The code is logged. 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. |
| 16-5 Cylinder #16 Injector current below normal | The ECM detects an open circuit. | The code is logged. The ECM continues to fire the injector solenoid. |
| 16-6 Cylinder #16 Injector current above normal | The ECM detects a short circuit. | The code is logged. 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. |
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 in the solenoid circuit, 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 of the 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.
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 "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 change in "Delivered Fuel Volume" for the remaining cylinders will be less than the change for a good injector. 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".
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".
 | |
| Illustration 1 | g01261239 |
Typical schematic | |
Test Step 1. Inspect the Electrical Connectors and the Wiring
- Turn the keyswitch to the OFF position.
- Thoroughly inspect the J2/P2 ECM connector. Inspect all of the injector connectors. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for details.
 | |
| Illustration 2 | g01234146 |
Location of ECM connectors | |
- Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
 | |
| Illustration 3 | g01261235 |
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 (P2-32) Injector cylinder #13 power (P2-33) Injector cylinder #13 return (P2-60) Injector cylinder #14 power (P2-61) Injector cylinder #14 return (P2-5) Injector cylinder #15 power (P2-18) Injector cylinder #15 return (P2-26) Injector cylinder #16 power (P2-27) Injector cylinder #16 return | |
- Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
- 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
- Connect Cat ET to the service tool connector.
- Turn the keyswitch to the ON position.
- Check for logged diagnostic codes for the injector solenoids on Cat ET.
- Turn the keyswitch to the OFF position.
Expected Result:
No 1-5 to 12-5 or 1-6 to 12-6 diagnostic codes are logged.
Results:
- OK - No 1-5 to 12-5 or 1-6 to 12-6 diagnostic codes are logged. There may be a problem with an injector. Proceed to Test Step 3.
- Not OK - A 1-5 to 12-5 diagnostic code is logged. Proceed to Test Step 4.
- Not OK - A 1-6 to 12-6 diagnostic code is logged. Proceed to Test Step 5.
Test Step 3. Perform the "Cylinder Cutout Test"
- Start the engine.
| 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. |
- Apply a load to the engine.
- Perform the following steps on all suspect cylinders (solenoids).
- Access the diagnostic tests on Cat ET. Initiate the "Cylinder Cutout Test".
- Disable the suspect cylinder(s) and the cylinders that are not suspect during the test. As each cylinder is disabled, monitor the change in the fuel position of the remaining cylinders.
Note: When a cylinder that has good performance is disabled, a large increase in the fuel position for the remaining cylinders will be noticed.
When a cylinder that has poor performance is disabled, a small increase in the fuel position for the remaining cylinders will be noticed. This may be an indication of a bad injector or a mechanical problem in the cylinder.
Expected Result:
The results indicated a proportional change in the fuel position when the "Cylinder Cutout Test" disabled each injector.
Results:
- OK - There was a proportional change in the fuel position when each of the cylinders were disabled.
Repair: The injectors appear to be operating properly in all cylinders. Clear all logged diagnostic codes. If an intermittent electrical problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".
STOP
- Not OK - There was an unbalanced change in the fuel position for one or more cylinders.
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. Be sure to program the trim code from the new injector into the ECM.
STOP
Test Step 4. Check the Harness Between the ECM and the Injector Connectors for an Open Circuit
- Ensure that the keyswitch is in the OFF position.
 |
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. |
 |
- Disconnect the connector for the suspect injector(s).
- Fabricate a jumper wire that is long enough to create a short circuit across the terminals of the injector connector. Crimp connector pins to each end of the jumper wire.
- Use the jumper wire to create a short circuit on the harness side of the connector for the suspect injector.
- Turn the keyswitch to the ON position.
- Access the diagnostic tests on Cat ET. Initiate the "Injector Solenoid Test". Allow the test to cycle through the cylinders at least two times.
- Record the results of the "Injector Solenoid Test".
- Turn the keyswitch to the OFF position.
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 7.
- Not OK - Cat ET displays "Open" for the cylinder with the jumper wire. There is a problem in the wiring between the ECM and the injector connector. Proceed to Test Step 6.
Test Step 5. Check the Harness Between the ECM and the Injector Connectors for a Short Circuit
- Ensure that the keyswitch is in the OFF position.
|
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. |
|
- Disconnect the connector for the suspect injector(s).
- Turn the keyswitch to the ON position.
- Access the diagnostic tests on Cat ET. Initiate the "Injector Solenoid Test". Allow the test to cycle through the cylinders at least two times.
- Record the results of the "Injector Solenoid Test".
- Turn the keyswitch to the OFF position.
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 7.
- Not OK - One or more cylinders indicate "Short" on Cat ET. Note the cylinders that indicate "Short". Proceed to Test Step 6.
Test Step 6. Check the ECM for Proper Operation
- Ensure that the keyswitch is in the OFF position.
|
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. |
|
- Create an open circuit at the ECM and perform the "Injector Solenoid Test".
- Disconnect the J2/P2 ECM connectors.
- Fabricate a jumper wire that is long enough to create a test circuit from the ECM connector to the engine ground stud. Crimp a connector socket to one end of the jumper wire.
- Remove the signal wire for the suspect injector from the appropriate terminal location at the P2 ECM connector. Install the jumper wire into this terminal location.
Note: Ensure that the loose end of the jumper wire is not in contact with any ground source.
- Connect the J2/P2 ECM connector.
- Turn the keyswitch to the ON position.
- Access the diagnostic tests on Cat ET. Initiate the "Injector Solenoid Test". Allow the test to cycle through the cylinders at least two times.
- Record the results of the "Injector Solenoid Test".
- Turn the keyswitch to the OFF position.
- Create a short circuit at the ECM and perform the "Injector Solenoid Test".
- Connect the wire jumper to the engine ground.
- Turn the keyswitch to the ON position.
- Access the diagnostic tests on Cat ET. Initiate the "Injector Solenoid Test". Allow the test to cycle through the cylinders at least two times.
- Record the results of the "Injector Solenoid Test".
- Turn the keyswitch to the OFF position.
- Restore the wiring to the original configuration.
Expected Result:
Cat ET displays "Open" when the signal wire for the injector is removed from the ECM connector. Cat ET displays "Short" when the wire jumper is shorted to engine ground.
Results:
- OK - The ECM is operating properly. The problem is in the wiring between the ECM and the injector connector.
Repair: Repair the harness and/or the connector. Refer to 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 7. Measure the Resistance of the Injector Solenoid
- Ensure that the keyswitch is in the OFF position.
- Disconnect the connectors for the suspect injector(s).
|
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. |
|
- Measure the solenoid resistance between the terminals at the injector solenoid.
- Record the measured resistance for each solenoid.
Expected Result:
The resistance is 1.06 ± 0.05 Ohms.
Results:
- OK - The resistance is 1.06 ± 0.05 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 ± 0.05 Ohms.
Repair: Replace the injector. Be sure to program the ECM with the trim code for the new injector. Verify that the problem is resolved.
STOP