What causes a vacuum leak?

Vacuum leaks are commonly caused by cracked or disconnected vacuum hoses, damaged intake manifold gaskets, or a leaking throttle body gasket. They cause the engine to run lean.

How much does it cost to fix intake system issues?

Intake repairs range from $20 for a new air filter to $500+ for MAF sensor or intake manifold gasket replacement. Vacuum hose repairs are typically inexpensive.

P0100

Mass or Volume Air Flow Circuit Malfunction

Moderateintake

Overview

The P0100 code indicates the PCM has detected a mass or volume air flow circuit malfunction condition in the air intake system. This code relates to the components that meter and deliver air to the engine, which is essential for proper air-fuel mixture and combustion. Issues in the intake system directly impact engine performance and fuel economy.

Symptoms

Poor fuel economy
Check Engine Light (MIL) illuminated
Reduced engine power
Poor acceleration

Common Causes

Faulty MAP (Manifold Absolute Pressure) sensor
Intake air temperature sensor malfunction
Dirty or faulty Mass Air Flow (MAF) sensor
Clogged air filter

Diagnosis Steps

1Connect an OBD-II scanner and read all stored trouble codes and freeze frame data
2Inspect the air filter and replace if dirty
3Clean or replace the MAF sensor using MAF-safe cleaner
4Check for vacuum leaks using a smoke machine or by spraying carb cleaner around intake connections
5Inspect the intake manifold gasket for leaks

Estimated Repair Cost

$100 — $500

Cost varies by vehicle, location, and repair shop. Includes parts and labor.

Commonly Affected Vehicles

Volkswagen JettaSubaru LegacyHonda AccordToyota Camry

Related Codes

P0101 P0174 P0105

More Intake Codes

P0068MAP/MAF - Throttle Position Correlation

Moderate

P0069Manifold Absolute Pressure - Barometric Pressure Correlation

Moderate

P0101Mass or Volume Air Flow Circuit Range/Performance

Moderate

P0102Mass or Volume Air Flow Circuit Low Input

Moderate

P0103Mass or Volume Air Flow Circuit High Input

Moderate

P0104Mass or Volume Air Flow Circuit Intermittent

Moderate

Frequently Asked Questions

Yes, a dirty MAF sensor can often be restored by cleaning with MAF-specific sensor cleaner. This is a common and affordable fix that should be tried before replacing the sensor.