Diagnostic trouble code P0101 indicates a Mass Air Flow (MAF) sensor range or performance problem.
Mass Air Flow sensors measure air flow entering the engine. Range performance codes are typically caused by unexpected MAF frequencies detected at the sensor.
A common cause for this code could be the overuse of filter oil on washable aftermarket air filters, which may cause MAF sensor wire contamination. If oil contamination is suspected, cleaning the MAF sensor may solve the problem. Look for obstructions in the air intake system, exhaust system, proper MAF installation (many MAF sensors have airflow direction arrows so this can be avoided), missing clamps or damaged intake components between the sensor and engine.
GM Code Tips for P0101
Code P0101 may occur on Chevy and GMC vehicles with clogged catalytic converters - or - otherwise restricted exhaust systems. The underlying cause of damaged converters may stem from leaking fuel pressure regulators which have been seen on certain Chevrolet and GMC trucks. Manifold Pressure (MAP) sensor problems and dirty throttle plates are also contributors for this code.