Diagnosing a P0172 Rich Condition: How MAF Contamination Can Mislead Technicians
In this Tech Tip Short, Erik Screeden walks technicians through a real-world diagnostic scenario involving a P0172 rich condition and P015B delayed oxygen sensor response on a 5.3L GMC truck. Instead of jumping straight to parts replacement, Screeden demonstrates how effective mass air flow sensor diagnostics and careful fuel trim diagnostics can reveal the true cause of drivability issues.
A contaminated MAF from an over-oiled air filter altered airflow readings, leading to incorrect fueling and a bank-specific fault. By focusing on condition, cause and correction, Screeden shows how technicians can avoid misdiagnosis. Watch the full Tech Tip Short to better understand MAF contamination symptoms and accurate diagnostic strategy.
About the Author
Erik Screeden
Technical and Multimedia Content Director
Erik Screeden is the Technical and Multimedia Content Director for the Vehicle Service & Repair Group. Erik is an ASE Master Automobile Technician with L1, and L4 credentials, who has been in the industry for over 25 years in various capacities. During that time, Screeden was a technician. He started out at a Ford dealership and continued to several independent repair facilities as well as spent time in the specialty aftermarket at a GM-specific performance shop. After his time as a technician came to an end, Screeden transitioned into a role providing scan diagnostic and J2534 tool support. He was then able to parlay his experience as a technician and a support specialist and use that in several technical sales roles.
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