Circuit/System Testing
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. 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 (Without FPCM) , or Fuel System Diagnosis (FPCM)
- 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
- Disconnect the appropriate component: Spark Plug Wire @ Spark Plug
- 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 @ Spark Plug Wire & Ground
- Engine - Running
- Verify there is spark at the tool.
- If there is no spark
- Remove the appropriate component: Spark Plug Wire
- Test for 1, 850 to 2, 250 ohms between the test points: Each terminal of the component
- If not between 1, 850 and 2, 250 ohms
Replace the component: Spark Plug Wire
- If between 1, 850 and 2, 250 ohms
Refer to: Alcohol/Contaminants-in-Fuel Diagnosis
- If not between 1, 850 and 2, 250 ohms
- 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
- 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 - 8 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.