P2004 on Mercedes-Benz
Intake Manifold Runner Control Stuck Open (Bank 1)
P2004 on Mercedes-Benz vehicles indicates intake manifold runner control stuck open (bank 1). Au7o has documented this code across 3 Mercedes-Benz models — most commonly on G-Class, M-Class, Sprinter. 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 Mercedes-Benz range from $50 to $900, 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 Mercedes-Benz by Model
Mercedes-Benz G-Class(1 issue)
- OM642 Diesel Intake Manifold Swirl Flap (Runner) Failure2005-2018
On diesel G-Class models with the OM642 V6, the plastic intake-manifold swirl flap linkage becomes brittle and snaps, and the swirl-flap actuator motor can fail (often after being contaminated by oil weeping from the turbo inlet seal). The broken plastic rods can also be drawn into the engine in worst cases. This is a well-known weak point that triggers intake-runner control faults, limp mode, and emissions test failures. Particularly relevant to higher-mileage EU diesel examples.
Mercedes-Benz M-Class(1 issue)
- OM642 Diesel Intake Swirl Flap and Linkage (Swirl Rod) Failure2006-2015
The OM642 3.0L V6 diesel in the ML320/350 CDI and BlueTEC uses intake manifold swirl flaps actuated by plastic linkage rods ('swirl rods') and an electric swirl motor. Constant under-hood heat cycling makes the plastic linkage brittle, while carbon and oil from the crankcase breather make the flaps sticky; the combination snaps the plastic rods. Oil weeping from the turbo inlet seal can also drip onto and kill the swirl motor. The result is rough idle, power loss, an illuminated MIL and possible failed emissions inspection - a relevant concern for EU diesel periodic inspection.
Mercedes-Benz Sprinter(1 issue)
- Intake Manifold Swirl Flap Linkage Breakage (P2015)2007-2018
The OM642 V6 intake manifolds use plastic swirl/runner flaps driven by a small actuator through a plastic connecting linkage. Oil mist and heat make the plastic linkage and pivots brittle; they crack and break, leaving the flaps stuck and triggering P2015 (and runner-control codes). A failed swirl-flap motor (often from an oil leak into the actuator) produces the same fault. The result is rough idle, power loss, a lit engine light and limp mode.
Looking for P2004 on a different make?
View P2004 across all makes →Frequently Asked Questions
What does P2004 mean on Mercedes-Benz?▼
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 Mercedes-Benz specifically, this code is documented across 3 models.
What causes P2004 on Mercedes-Benz vehicles?▼
Common causes on Mercedes-Benz: 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 Mercedes-Benz?▼
Repair costs on Mercedes-Benz range from $50 to $900, depending on the specific model and root cause.
Which Mercedes-Benz models have P2004 documented?▼
Au7o has documented P2004 on 3 Mercedes-Benz models: G-Class, M-Class, Sprinter.