5031887 JOHNSON O RING (D:2.4 ID:41.7)

Table 1
Diagnostic Codes Table
Code and Description 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 engine's 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 engine's 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 engine's 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 engine's 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 engine's 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. 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, 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 2. Two injector solenoids share a supply wire. For this reason, an open circuit or a short circuit in a supply wire or a connector could cause diagnostic codes for two injector solenoids. Note that a diagnostic code for a single injector indicates that the problem is most likely in the return wire or a connector in the return circuit. When an injector is replaced, you must program the new injector trim files into the ECM. If the ECM is replaced, all injector trim files must be programmed into the new ECM. Refer to Troubleshooting, "Injector Trim File - Install" for more information.Caterpillar Electronic Technician (ET) includes the following tests that aid in troubleshooting the injector solenoids:"Cylinder Cutout Test"The "Cylinder Cutout Test" is used on an engine in order to determine the individual cylinder performance while the engine is running. As one or more cylinders are cut out during the test, the "Cylinder Cutout Test" uses the "Fuel Position" of each injector in order to evaluate the performance of the remaining cylinders that are firing. As the different cylinders are cut out, a comparison of the change in "Fuel Position" is used to identify cylinders that are weak or misfiring. One reason for a cylinder that is weak or misfiring is an injector that is malfunctioning mechanically.During the test, when a good injector is cut out, the "Fuel Position" of the remaining injectors will show a consistent change. This consistent change in the "Fuel Position" is caused by the remaining injectors that are compensating for the cut out injector. If a malfunctioning injector is cut out, the "Fuel Position" will not show a proportional change. This unbalanced change is the result of the smaller quantity of fuel that is needed to compensate for the power loss from the malfunctioning injector. The "Cylinder Cutout Test" is used to isolate a malfunctioning injector in order to avoid replacement of injectors that are in good repair.Note: Prior to running the "Cylinder Cutout Test", all active diagnostic codes must be repaired."Injector Solenoid Test"Use the "Injector Solenoid Test" to diagnose an open circuit or a short circuit in the wiring for the injector solenoids. While the engine is off, the "Injector Solenoid Test" briefly activates each injector solenoid. A good solenoid will create an audible click when the solenoid is activated. After performing