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.
- Ignition - On / Vehicle - In Service Mode
- Verify the scan tool parameter: MAF Sensor = 5 to 40 g/s
- If not between 5 and 40 g/s
Verify the following conditions do not exist:
- Intake Manifold - Leaking
- Intake Air Duct - Loose Clamps/Cracked/Visible Damage
- Mass Airflow Sensor - Contamination of the measuring element/Water intrusion
- If a condition exists
Repair or replace as necessary.
- If no condition exists
Refer to: Diesel Particulate Filter (DPF) Service Regeneration
- If a condition exists
- Go to next step: If between 5 and 40 g/s
- If not between 5 and 40 g/s
- Ignition/Vehicle - Off
- Verify a condition does not exist with the component:
- Exhaust System - Leaking/Missing components/Restricted - Refer to: Symptoms - Engine Exhaust
- Fuel - Contaminated/Poor Quality - Refer to: Contaminants-in-Fuel Diagnosis , & Fuel System Specifications
- Q17 Fuel Injector - Leaking/Restricted - Refer to: Fuel Injector Balance Test - Circuit/System Testing
- If a condition exists
Repair or replace as necessary.
- Go to next step: If no condition exists
- Perform a conventional engine compression test. Refer to: Engine Compression Test
- If one or more cylinders indicate low compression
Refer to: Symptoms - Engine Mechanical
- Go to next step: If all cylinders indicate normal compression
- If one or more cylinders indicate low compression
- Replace the component: B195A Nitrogen Oxides Sensor 1