2010 Cadillac Truck Escalade RWD V8-6.2L Page 1997
3. Observe the Misfire Current Counters with a scan tool. The Misfire Current Counters should not be incrementing. Random misfires that are
not steadily incrementing may be normal.
4. Operate the vehicle within the Conditions for Running the DTC to verify that the DTC does not reset. You may also operate the vehicle
within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Important: You must perform the Circuit/System Verification first.
1. Verify that the following conditions do not exist:
* The fuel injector wire harness electrical connectors are connected to the wrong fuel injectors. Refer to Engine Controls Schematics (See:
Diagrams/Electrical Diagrams/Powertrain Management/System Diagram).
* Engine vacuum leaks
* Fuel pressure that is too low or too high-Refer to Fuel System Diagnosis (w/o FPCM) (See: Powertrain Management/Computers and
Control Systems/Testing and Inspection/Component Tests and General Diagnostics)Fuel System Diagnosis (FPCM) (See: Powertrain
Management/Computers and Control Systems/Testing and Inspection/Component Tests and General Diagnostics).
* Contaminated fuel-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool) (See: Powertrain Management/Computers
and Control Systems/Testing and Inspection/Component Tests and General Diagnostics/Alcohol/Contaminants-in-Fuel Diagnosis
(Without Special Tool))Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool) (See: Powertrain Management/Fuel Delivery and Air
Induction/Fuel/Testing and Inspection/Alcohol/Contaminants-in-Fuel Diagnosis (Special Tool)).
* Restricted exhaust system-Refer to Restricted Exhaust (See: Engine, Cooling and Exhaust/Exhaust System/Testing and
Inspection/Restricted Exhaust).
瀚慖f you find any of the above conditions, repair as necessary.
2. Verify that there is no misfire on cylinders 1, 4, 6, or 7 due to cylinder deactivation-Refer to Cylinder Deactivation (Active Fuel
Management) System Diagnosis (See: Powertrain Management/Computers and Control Systems/Testing and Inspection/Component Tests
and General Diagnostics/Cylinder Deactivation (Active Fuel Management) System Diagnosis).
3. Ignition OFF, install the J 26792 - Tester to the spark plug wire boot of the misfiring cylinder.
Note: An erratic or weak spark is considered a no spark condition.
4. Attempt to start the engine and observe the J 26792 - Tester. The spark tester should spark.
瀚慖f there is no spark, test the spark plug wire for the correct resistance, refer to Ignition System Specifications (See: Powertrain
Management/Ignition System/Specifications) and Spark Plug Wire Inspection (See: Engine, Cooling and Exhaust/Engine/Tune-up and
Engine Performance Checks/Ignition Cable/Testing and Inspection).
瀚慖f the spark plug wire tests normal, refer to Electronic Ignition System Diagnosis (See: Powertrain Management/Computers and Control
Systems/Testing and Inspection/Component Tests and General Diagnostics/Electronic Ignition System Diagnosis) for diagnosis of the
ignition coil.
5. Ignition OFF, remove the spark plug from the misfiring cylinder. Verify that the following conditions do not exist with the spark plug:
* Gas, coolant, or oil fouled
* Cracked, worn, or incorrectly gapped-Refer to Spark Plug Inspection (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine
Performance Checks/Spark Plug/Testing and Inspection).
瀚慖f there is a condition with the spark plug, replace the spark plug.
6. Exchange the suspected spark plug with another cylinder that is operating correctly.
7. Operate the engine under the conditions in which the misfire occurred. This may include putting the engine under a load or allowing the
engine to return to a cold condition. Observe the Misfire Current Counters with a scan tool. The misfire should not follow the spark plug
exchange.
瀚慖f the misfire follows with the spark plug, replace the spark plug.
8. If all conditions test normal, test or inspect for the following:
* A lean or rich fuel injector-Refer to Fuel Injector Diagnosis (CH47976) (See: Powertrain Management/Fuel Delivery and Air
Induction/Fuel Injector/Testing and Inspection)Fuel Injector Diagnosis (J39021 or Scan Tool) (See: Powertrain Management/Fuel
Delivery and Air Induction/Fuel Injector/Testing and Inspection).
* An engine mechanical condition-Refer to Symptoms - Engine Mechanical (See: Engine, Cooling and Exhaust/Engine/Testing and
Inspection/Symptom Related Diagnostic Procedures/Symptoms - Engine Mechanical).
Repair Instructions
* Spark Plug Wire Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Ignition Cable/Service
