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.

P2004

Intake Manifold Runner Control Stuck Open (Bank 1)

Moderateintake

Overview

The P2004 code indicates the PCM has detected a intake manifold runner control stuck open (bank 1) 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

Whistling or hissing noise from engine bay
Hesitation during acceleration
Poor fuel economy
Check Engine Light (MIL) illuminated

Common Causes

Stuck or failed intake manifold runner control
Dirty or faulty MAF sensor
Vacuum leak in intake system
Carbon buildup on intake valves

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 carb cleaner around intake connections
5Inspect the intake manifold runner control valve for stuck or damaged operation

Estimated Repair Cost

$100 — $500

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

Commonly Affected Vehicles

Mazda 6Honda AccordChevrolet MalibuVolkswagen Jetta

Related Codes

P0100 P0101 P0105

More Intake Codes

P0068MAP/MAF - Throttle Position Correlation

Moderate

P0069Manifold Absolute Pressure - Barometric Pressure Correlation

Moderate

P0100Mass or Volume Air Flow Circuit Malfunction

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

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.