The GM Service Guy

Valve Cover Leaks: Meaning, Symptoms & Repair Guide for GM Vehicles A leaking valve cover gasket is one of the most common oil leaks on GM engines — and if...

5.3L AFM Failure: Meaning, Symptoms & Repair Guide for GM Trucks Active Fuel Management is GM's cylinder-deactivation system for improving fuel economy on the 5.3L V8 — but when the...

5.3L Lifter Noise: Meaning, Symptoms & Repair Guide for GM Trucks That cold-start tick coming from your 5.3L is one of the most common complaints on GM trucks and SUVs...

P0430 Code: Catalyst System Efficiency Below Threshold, Bank 2 (GM Diagnosis & Repair Guide) P0430 is the bank 2 counterpart to P0420, and on most GM V8s that means the...

P0420 Code: Catalyst System Efficiency Below Threshold, Bank 1 (GM Diagnosis & Repair Guide) P0420 has a reputation for being expensive, but it's also one of the most misdiagnosed codes...

P0521 Code: Engine Oil Pressure Sensor/Switch Range/Performance (GM Diagnosis & Repair Guide) P0521 is a code that can mean anything from a $30 sensor fix to a serious oiling problem,...

P1682 Code: Ignition 1 Switch Circuit 2 Malfunction (GM Diagnosis & Repair Guide) P1682 is a GM-specific electrical code that causes some of the most frustrating intermittent no-start complaints on...

P0171 Code: System Too Lean, Bank 1 (GM Diagnosis & Repair Guide) P0171 is a fuel trim code that shows up constantly on GM vehicles, and while it's rarely an...