825502 Mercury SCREW

Table 1
Diagnostic Trouble Codes for the Injectors    
J1939 Code    Description    Information    
651-5     Engine Injector Cylinder #01 : Current Below Normal     The ECM monitors the current flow through the circuit for each injector solenoid. If low current flow (open circuit) is detected, a diagnostic code is activated. The ECM continues to try to fire the injector. If high current flow (short circuit) is detected, a diagnostic code is activated. The ECM will disable the solenoid circuit in order to prevent damage from the high current flow. However, 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.    
651-6     Engine Injector Cylinder #01 : Current Above Normal    
652-5     Engine Injector Cylinder #02 : Current Below Normal    
652-6     Engine Injector Cylinder #02 : Current Above Normal    
653-5     Engine Injector Cylinder #03 : Current Below Normal    
653-6     Engine Injector Cylinder #03 : Current Above Normal    
654-5     Engine Injector Cylinder #04 : Current Below Normal    
654-6     Engine Injector Cylinder #04 : Current Above Normal    
655-5     Engine Injector Cylinder #05 : Current Below Normal    
655-6     Engine Injector Cylinder #05 : Current Above Normal    
656-5     Engine Injector Cylinder #06 : Current Below Normal    
656-6     Engine Injector Cylinder #06 : Current Above Normal    
651-2     Engine Injector Cylinder #01 : Erratic, Intermittent, or Incorrect     The code is logged. The ECM continues to energize the injector solenoid.
The Fuel System Verification Test must be performed in order to clear a -7 code.    
651-7     Engine Injector Cylinder #01 : Not Responding Properly    
652-2     Engine Injector Cylinder #02 : Erratic, Intermittent, or Incorrect    
652-7     Engine Injector Cylinder #02 : Not Responding Properly    
653-2     Engine Injector Cylinder #03 : Erratic, Intermittent, or Incorrect    
653-7     Engine Injector Cylinder #03 : Not Responding Properly    
654-2     Engine Injector Cylinder #04 : Erratic, Intermittent, or Incorrect    
654-7     Engine Injector Cylinder #04 : Not Responding Properly    
655-2     Engine Injector Cylinder #05 : Erratic, Intermittent, or Incorrect    
655-7     Engine Injector Cylinder #05 : Not Responding Properly    
656-2     Engine Injector Cylinder #06 : Erratic, Intermittent, or Incorrect    
656-7     Engine Injector Cylinder #06 : Not Responding Properly    
Follow the troubleshooting procedure in order to identify the root cause of the problem.    Note: The Not Responding Properly -7 diagnostic codes can be caused by an old fuel pressure regulator. For details, refer to Truck Engine News, SEBD68111 April 2008, "A New Fuel Pressure Regulator Is Now Used".Background InformationTypically, problems with an injector solenoid occur when the engine is warmed up and/or when the engine is under vibration (heavy loads). Perform this procedure when the engine is at normal operating temperature. Pay careful attention to the condition of the wiring and the connectors as you perform this procedure. The wiring and/or the connectors may have problems that only occur during vibration.These engines have Electronic Unit Injectors (EUI) that are electronically controlled. Each injector contains a solenoid. The Engine Control Module (ECM) sends 105 V pulses to each injector solenoid. The pulses are sent at the proper time and at the correct duration for a given engine load and speed.Cooling of the Injector SolenoidsEach injector solenoid is cooled by a stream of oil. The stream of oil exits from a hole in the exhaust valve rocker arm. The stream of oil must be checked whenever an injector is replaced.Diagnostic Tests on the Caterpillar Electronic Technician (ET)Cat ET includes the following test that aids in troubleshooting injector solenoids:Injector Solenoid Test - This test identifies an open circuit or a short circuit in the circuits for the injector solenoids. The test is performed 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 indicates the status of the solenoid as "OK", "Open", or "Short".Fuel System Verification Test - This test evaluates the health of each injector. The test determines if an injector needs to be replaced. When the test is performed, Cat ET indicates the status of each injector as "Success" or "Failed". Perform this test immediately after an injector has been replaced. Also, perform this test if a –2 code is active or a –7 code is active.Note: Refer to the following schematics. Two injector solenoids share a common supply wire. For this reason, an open circuit or a short circuit in a supply wire could cause diagnostic codes for two cylinders.
Illustration 1 g01404811
Schematic for the injector solenoids on C7 engines
Illustration 2 g01404719
Schematic for the injector solenoids on C7 enginesTest Step 1. Determine the Diagnostic Code
Establish communication between Cat ET and the engine ECM. Cat ET must be communicating on both data links in order to perform this procedure. Refer to Troubleshooting, "Electronic Service Tools", if necessary.
Determine the diagnostic trouble code that relates to an injector.Expected Result:A -2 code or a -7 code is present.Results:
A -2 code or a -7 code is present. - Repair: Perform the following procedure:
Do not clear the diagnostic trouble code.
Illustration 3 g01404206
Accessing the Fuel System Verification Test
Perform the Fuel System Verification Test. Cat ET will clear the code when the test begins.If the injector passes the test, the injector is okay. STOP. If the injector fails the test, proceed to Test Step 10.
A -5 code or a -6 code is present. - Proceed to Test Step 2.Test Step 2. Determine if the Code is Active or Logged
Start the engine. Allow the engine to warm up to normal operating temperature 77 °C (171 °F).
Determine if the code is active or logged.Expected Result:The code is logged.Results:
Logged code - Do not turn off the engine. Proceed to Test Step 3.
Active code - Do not turn off the engine. Proceed to Test Step 5.Test Step 3.