Yukon XL 4WD V8-5.3L (2011)
Ignition Coil: Testing and Inspection
Electronic Ignition System Diagnosis
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
This ignition system uses individual ignition module/coil assemblies for each cylinder. The engine control module (ECM) controls the spark events by
transmitting the timing pulses on the ignition control (IC) circuits to the individual ignition module/coil assemblies in firing order sequence. Each
ignition module/coil has the following circuits:
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An ignition 1 voltage circuit
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A ground circuit
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An IC circuit
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A low reference circuit
Diagnostic Aids
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This test procedure requires that the vehicle battery has passed a load test and is completely charged.
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There is an adequate supply of fuel in the fuel tank.
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When disconnecting electrical connectors or removing fuses and relays from a fuse block, always inspect both mating electrical terminals for
corrosion and terminal tightness.
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Use the J 35616 for any test that requires probing the underhood fuse block terminals, component wire harness terminals, or the ECM wire
harness terminals.
Reference Information
Schematic Reference
Engine Controls Schematics See: Diagrams/Electrical Diagrams/Wiring Schematic Index
Connector End View Reference
Component Connector End Views See: Diagrams/Connector Views/Connector End Views By Name
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
Scan Tool Reference
Control Module References See: Testing and Inspection/Programming and Relearningfor scan tool information
Special Tools
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J 26792 Spark Plug Tester
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J 35616-A/BT-8637 Connector Test Adapter Kit
Circuit/System Verification
Observe the Engine Controls Schematic for the ignition module/coils, and review the Ignition System Specifications to verify the following concerns:
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The ignition modules/coils are correctly wired and connected
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The proper spark plug type
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The proper spark plug gap and torque
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The proper ohm values for the spark plug wires
Refer to Ignition System Specifications See: Spark Plug/Application and ID.
