F1578 Force HEX HD SCREW W/ LOCKWASHER, 1/4 - 20 X 7/8

Illustration 1 g01336666
Typical example of the electronic unit injector
Test Step 1. Check for Diagnostic Codes that are Related to this Procedure
Connect the electronic service tool to the diagnostic connector.
Turn the keyswitch to the ON position.
Check for diagnostic codes that are related to this procedure.
Make a note of the diagnostic codes. Expected Result:Expected Result 1One or more of the following diagnostic codes are logged or active:
1-2 Cylinder #1 Injector erratic, intermittent, or incorrect
2-2 Cylinder #2 Injector erratic, intermittent, or incorrect
3-2 Cylinder #3 Injector erratic, intermittent, or incorrect
4-2 Cylinder #4 Injector erratic, intermittent, or incorrect
5-2 Cylinder #5 Injector erratic, intermittent, or incorrect (C6.6 engine only)
6-2 Cylinder #6 Injector erratic, intermittent, or incorrect (C6.6 engine only) Expected Result 2On four cylinder engines, two injectors that share a common supply indicate a diagnostic code.Note: Injectors 1 and 4 share a common injector driver circuit in the ECM. Injectors 2 and 3 share a common driver circuit in the ECM. If two injectors that share a common supply indicate a diagnostic code then this is probably caused by a faulty ECM.On six cylinder engines, three injectors that share a common supply indicate a diagnostic code.Note: Injectors 1, 2 and 3 share a common injector driver circuit in the ECM. Injectors 4, 5 and 6 share a common driver circuit in the ECM. If three injectors that share a common supply indicate a diagnostic code then this is probably caused by a faulty ECM.Results:
OK - Result 1 One or more diagnostic codes are logged. Proceed to Test Step 2.
OK - Result 2 On four cylinder engines, two injectors that share a common supply indicate a diagnostic code. On six cylinder engines, three injectors that share a common supply indicate a diagnostic code. Proceed to Test Step 3.
Not OK - No related diagnostic codes are logged.STOPTest Step 2. Check the Faulty Cylinder Numbers
Use the electronic service tool in order to identify the diagnostic codes.
Use the diagnostic codes in order to check the cylinders for faulty injectors. Expected Result:The diagnostic codes indicate the cylinder numbers that have faulty injectors.Results:
OK - No related diagnostic codes are logged.STOP
Not OK - The diagnostic codes indicate the cylinder numbers that have faulty injectors.Repair: Replace the faulty injectors.Use the electronic service tool in order to program the trim file for the replacement injector . Refer to Troubleshooting, "Injector Trim File" for further information.Use the electronic service tool in order to clear the logged codes.Turn the keyswitch to the ON position.Start the engine.Use the electronic service tool in order to perform the "Fuel System Verification Test". If the cylinders indicate "PASS", then the fault has been cleared.Verify that the repair eliminates the fault.STOPTest Step 3. Check the ECM
Make sure that the latest flash file for the application is installed in the ECM. Refer to Troubleshooting, "Flash Programming".
Contact the Technical Communicator. Note: This consultation can greatly reduce the repair time.
If the Technical Communicator recommends the use of a test ECM, install a test ECM. Refer to Troubleshooting, "Replacing the ECM".
Use the electronic service tool in order to perform the "Fuel System Verification Test". Verify that the test eliminates the fault. Note: The "Fuel System Verification Test" will indicate if the cylinder has a "Pass" or "Fail". If the cylinders indicate "Pass" then the fault has been cleared.
If the test ECM eliminates the fault, reconnect the suspect ECM.
Use the electronic service tool in order to perform the "Fuel System Verification Test". Expected Result:The test ECM clears the fault.Results:
OK - The test ECM eliminates the fault.Repair: Perform the following procedure:
Reconnect the suspect ECM.
Use the electronic service tool in order to perform the "Fuel System Verification Test".
If the fault returns with the suspect ECM, replace the ECM.
Use the electronic service tool in order to clear all logged diagnostic codes and then verify that the repair eliminates the fault. STOP
Not OK - The test ECM did not eliminate the fault.Repair: Repeat this test procedure from Test Step 1.STOP