CTS Wagon RWD V6-3.6L (2010)
Fuel Injector: Testing and Inspection
Fuel Injector Solenoid Coil Test (w/LLT)
Diagnostic Instructions
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Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
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Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
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Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure Instructions)
provides an overview of each diagnostic category.
Circuit/System Description
The engine control module (ECM) supplies a separate high voltage supply circuit and a high voltage control circuit for each fuel injector. The injector
high voltage supply circuit and the high voltage control circuit are both controlled by the ECM. The ECM energizes each fuel injector by grounding the
control circuit. The ECM controls each fuel injector with 65 V. This is controlled by a boost capacitor in the ECM. During the 65 V boost phase, the
capacitor is discharged through an injector, allowing for initial injector opening. The injector is then held open with 12 V. A fuel injector coil winding
resistance that is too high or too low will affect the engine driveability. 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.
Reference Information
Schematic Reference
Engine Controls Schematics (LLT) (See: Diagrams/Electrical Diagrams)Engine Controls Schematics (LF1) (See: Diagrams/Electrical Diagrams)
Electrical Information Reference
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Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
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Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
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Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
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Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
Component Testing
Note:
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The resistance test must be performed at the fuel injector or mis-diagnosis will occur.
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The DMM and test leads must be calibrated to 0 ohm in order to prevent mis-diagnosis.
Verify the resistance of each Q17 fuel injector with one of the following methods:
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If the engine coolant temperature (ECT) sensor is between 10-32°C (50-90°F), the resistance of each Q17 fuel injector should be 1.25-1.75 ohm.
‹› If not within the specified range, replace the Q17 fuel injector.
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If the ECT sensor is not between 10-32°C (50-90°F), measure and record the resistance of each Q17 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
0.45 ohm.
‹› If the difference is more than 0.45 ohm, 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 individual fuel injector resistance
value from the average resistance value. Compute the difference between the highest individual fuel injector resistance value and the average
resistance value. Replace the Q17 fuel injector that displays the greatest difference above or below the average.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Computers and Control Systems/Testing and Inspection/Diagnostic Trouble Code Tests and
Associated Procedures/Verification Tests and Procedures) after completing the diagnostic procedure.
Fuel Injector Replacement (See: Service and Repair/Fuel Injector Replacement)
