Diagnostic Instructions
Circuit/System Description
The engine control module (ECM) enables the appropriate fuel injector pulse for each cylinder. The ignition voltage is supplied directly to the fuel injectors. The ECM 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 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
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
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 Ω. |
⇒ | If the resistance of any fuel injector is not 11-14 Ω, 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 Ω |
⇒ | If the difference is more than 3 Ω, 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.
Fuel Injector and Fuel Rail Replacement.