Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.

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
Install - J-26792 Ignition Spark Tester @ T8 Ignition Coil & Ground
Engine - Running

NOTE:

An erratic or weak spark is considered a no spark condition.

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
Ignition/Vehicle - Off
Remove the appropriate component: Spark Plug
Verify the component specifications are correct: Spark Plug - Gap / Heat Range /Torque - Refer to: Ignition System Specifications
- If not correct
  Repair or replace as necessary
- Go to next step: If 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
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 - 4 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
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
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
All OK.