Circuit/System Testing
WARNING: This page is about a different car, the 2020 Buick Regal and 2019 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
- Verify the following conditions do not exist:
- Engine - Vacuum leak
- Exhaust System - Leaking/Missing components/Restricted - Refer to: Symptoms - Engine Exhaust
- Fuel - Contaminated/Dirty/Fill Level = Low - Refer to: Alcohol/Contaminants-in-Fuel Diagnosis
- Fuel Pressure - High/Low - Refer to: Fuel System Diagnosis
- Positive Crankcase Ventilation System - Leaking/Incorrect connection/Restricted
- Vacuum Hoses - Kinked/Leaking/Incorrect connection/Restricted
- If a condition exists
Repair or replace as necessary
- Go to next step: If no conditions exist
- Ignition/Vehicle - Off
- Remove the appropriate component: T8 Ignition Coil - Leave the electrical connector connected.
- Verify a condition does not exist with the component: Spark Plug Boot - Carbon Tracking/Fluid intrusion/Visible Damage
- If a condition exists
Repair or replace as necessary
- Go to next step: If no condition exists
- If a condition exists
- Install - J-26792 Ignition Spark Tester @ T8 Ignition Coil & Ground
- Engine - Running
- Verify there is spark at the tool.
- If there is no spark
Refer to: Electronic Ignition System Diagnosis
- Go to next step: If there is spark
- If there is no spark
- Ignition/Vehicle - Off
- Remove the appropriate component: Spark Plug
- Verify the component specifications are correct: Spark Plug - Gap / Heat Range /Torque - Refer to: Electronic Ignition System Diagnosis
- If not correct
Repair or replace as necessary
- Go to next step: If correct
- If not correct
- Verify a condition does not exist with the component: Spark Plug - Carbon Tracking/Fouled/Visible Damage
- If a condition exists
Repair or replace as necessary
- Go to next step: If no condition exists
- If a condition exists
- Swap the two components: Spark Plug - The original component that set the DTC & Another known good component from the vehicle
- Engine - Running
- Verify the scan tool parameter: Cylinder 1 - 6 Current Misfire Counter = Increments - At the original component location the DTC set.
- If the parameter value does not increment
Replace the component: Spark Plug - The original component that set the DTC
- Go to next step: If the parameter value increments
- If the parameter value does not increment
- Perform the following procedure/test: Fuel Injector Balance - Refer to: Fuel Injector Diagnosis
Verify the procedure/test passes.
- If the procedure/test does not pass
Replace the component that failed the test: Q17 Fuel Injector
- Go to next step: If the procedure/test passes
- If the procedure/test does not pass
- Verify the condition does not exist: An engine mechanical condition - Refer to: Symptoms - Engine Mechanical
- If a condition exists
Repair or replace as necessary
- Go to next step: If no condition exists
- If a condition exists
- All OK.
NOTE:
An erratic or weak spark is considered a no spark condition.