2010 Cadillac Truck SRX FWD V6-3.0L Page 1397
Note: An erratic or weak spark is considered a no spark condition.
5. Attempt to start the engine and observe the J 26792 - Spark Tester. The spark tester should spark.
瀚慖f there is no spark, 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.
6. Ignition OFF, remove the spark plug from the misfiring cylinder. Verify that the spark plug does not exhibit the following conditions:
* Gas, coolant, or oil fouled-Refer to Spark Plug Inspection (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance
Checks/Spark Plug/Testing and Inspection).
* Cracked, worn, incorrectly gapped-Refer to Ignition System Specifications (LAU) (See: Powertrain Management/Ignition
System/Specifications)Ignition System Specifications (LF1) (See: Powertrain Management/Ignition System/Specifications).
瀚慖f there is a condition with the spark plug, replace the spark plug.
7. Exchange the suspected spark plug with another cylinder that is operating correctly.
8. Engine idling, observe the scan tool Misfire Current Counter parameters. The misfire should not follow the spark plug exchange.
瀚慖f the misfire follows the spark plug, replace the spark plug.
9. If all conditions test normal, test or inspect for the following:
* A lean or rich Q17 fuel injector-Refer to Fuel Injector Solenoid Coil Test (LAU) (See: Powertrain Management/Fuel Delivery and Air
Induction/Fuel Injector/Testing and Inspection)Fuel Injector Solenoid Coil Test (LF1, LFW) (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
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Spark Plug Replacement (See: Engine, Cooling and Exhaust/Engine/Tune-up and Engine Performance Checks/Spark Plug/Service and
Repair)
* To verify that the performance of the catalytic converter has not been affected by the condition that set this DTC, perform the Repair
Verification for DTC P0420 or P0430. Refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code
Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle) for DTC P0420 or P0430.
P0304
DTC P0300-P0306 (LF1, LFW)
Diagnostic Instructions
* 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.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0300
- Engine Misfire Detected
DTC P0301
- Cylinder 1 Misfire Detected
DTC P0302
- Cylinder 2 Misfire Detected
DTC P0303
- Cylinder 3 Misfire Detected
DTC P0304
- Cylinder 4 Misfire Detected
