Diagnostic Fault Information
Perform the
Diagnostic System Check - Vehicle
,
prior to using this diagnostic procedure.
Circuit/System Description
The Control Module enables the appropriate fuel injector pulse for each cylinder.
The ignition voltage is supplied directly to the fuel injectors. The Control Module
controls each fuel injector by grounding the control circuit via a solid state device
called a driver. A fuel injector coil winding resistance that is too high or too low
will affect the engine driveability. A fuel injector control circuit DTC may not set
but a misfire may be apparent. The fuel injector coil windings are affected by temperature.
The resistance of the fuel injector coil windings will increase as the temperature
of the fuel injector increases.
Diagnostic Aids
| • | Monitoring the misfire current counters, or misfire graph, may help to
isolate the fuel injector that is causing the condition. |
| • | Operating the vehicle over a wide temperature range may help isolate the
fuel injector that is causing the condition. |
| • | Perform the Fuel Injector Solenoid Coil Test within the conditions of
the customers concern. A fuel injector condition may only be apparent at a certain
temperature or under certain conditions. |
Reference Information
Schematic Reference
Engine Controls Schematics
Electrical Information Reference
Component Testing
Verify the resistance of each fuel injector with one of the following methods:
| • | If the engine coolant temperature (ECT) sensor is between 10-32°C
(50-90°F), the resistance of each fuel injector should be 11-14 ohms. |
| ⇒ | If the resistance of any fuel injector is not 11-14 ohms, replace
the fuel injector. |
| • | If the ECT sensor is not between 10-32°C (50-90°F),
measure and record the resistance of each fuel injector with a DMM. Subtract the lowest
resistance value from the highest resistance value. The difference between the lowest
value and the highest value should be equal to or less than 3 ohms. |
| ⇒ | If the difference is more than 3 ohms, add all of the fuel injector resistance
values to obtain a total resistance value. Divide the total resistance value by the
number of fuel injectors to obtain an average resistance value. Subtract the lowest,
and the highest, individual fuel injector resistance values from the average resistance
value. Replace the fuel injector that displays the greatest resistance difference
above or below the average. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after
completing the diagnostic procedure.
Fuel Injector Balance Test with Special Tool
or
Fuel Injector Balance Test with Tech 2
