P2004 on Subaru
Intake Manifold Runner Control Stuck Open (Bank 1)
P2004 on Subaru vehicles indicates intake manifold runner control stuck open (bank 1). Au7o has documented this code across 1 Subaru model — most commonly on WRX STI. P2004 means the intake manifold runner control for engine bank 1 is stuck in the open position. Many engines use flaps or valves inside the intake manifold that close at low RPM to boost air velocity and torque, then open at higher RPM; this code sets when the computer commands those runners to close but a sensor shows they remain open. The result is usually rough low-speed running, reduced low-end power, or hesitation. It indicates a mechanical or actuator problem in the variable intake system, not a true vacuum or fuel issue. Typical repair costs on Subaru range from $250 to $1,400, depending on the specific model and root cause.
Common Causes of P2004
- •Stuck or seized intake manifold runner flaps (carbon buildup)
- •Failed intake manifold runner control actuator or solenoid
- •Disconnected or broken actuator linkage/rod
- •Faulty intake runner position sensor
- •Damaged wiring or connector at the actuator/sensor
- •Vacuum leak or failed vacuum supply on vacuum-operated systems
- •Cracked or warped intake manifold
P2004 on Subaru by Model
Subaru WRX STI(1 issue)
- Tumble Generator Valve (TGV) Sensor/Motor Fault (P2004/P2005/P2011/P2016)2004-2014
WRX STI models with EJ257 intake TGV assemblies can develop failures in the TGV position sensors or actuator mechanisms, leading to stuck-open/stuck-closed conditions. Owners report check engine lights, rough cold starts, and reduced drivability, especially in colder weather. This issue is frequently discussed in owner reports and appears in diagnostic guidance/TSBs for Subaru intake runner control/TGV-related DTCs.
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What does P2004 mean on Subaru?▼
P2004 stands for "Intake Manifold Runner Control Stuck Open (Bank 1)." P2004 means the intake manifold runner control for engine bank 1 is stuck in the open position. Many engines use flaps or valves inside the intake manifold that close at low RPM to boost air velocity and torque, then open at higher RPM; this code sets when the computer commands those runners to close but a sensor shows they remain open. The result is usually rough low-speed running, reduced low-end power, or hesitation. It indicates a mechanical or actuator problem in the variable intake system, not a true vacuum or fuel issue. On Subaru specifically, this code is documented across 1 model.
What causes P2004 on Subaru vehicles?▼
Common causes on Subaru: Stuck or seized intake manifold runner flaps (carbon buildup), Failed intake manifold runner control actuator or solenoid, Disconnected or broken actuator linkage/rod, Faulty intake runner position sensor, Damaged wiring or connector at the actuator/sensor. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P2004 on a Subaru?▼
Repair costs on Subaru range from $250 to $1,400, depending on the specific model and root cause.
Which Subaru models have P2004 documented?▼
Au7o has documented P2004 on 1 Subaru model: WRX STI.