ELECTRONIC TECHNICIAN (ET) TROUBLESHOOTING - Continued
Injector Solenoid Circuit Test.
System Operation Description:
An injector solenoid may have a problem.
You have been directed to this procedure from Troubleshooting, Troubleshooting without a Diagnostic
There is an active diagnostic code for an injector solenoid.
Use this procedure for the following diagnostic codes:
1-E-11 Injector Cylinder 1 fault
2-E-11 Injector Cylinder 2 fault
3-E-11 Injector Cylinder 3 fault
4-E-11 Injector Cylinder 4 fault
5-E-11 Injector Cylinder 5 fault
6-E-11 Injector Cylinder 6 fault
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 hydraulically actuated electronically controlled unit injectors
(HEUI). 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. The Caterpillar Electronic Technician (ET) includes the
following tests that aid in troubleshooting the injector solenoids.
Prior to running the Cylinder Cutout Test, all active diagnostic codes must be repaired.
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.