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 conditions exist
Install the special tool : 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 the component specifications are correct : Spark Plug - Carbon Tracking/Fouled/Visible Damage
- If a condition exists
  Repair or replace as necessary.
- Go to next step : If no conditions exist
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 (NTB) , or 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.