Air intakeGeneric OBD-II codeUrgency: Monitor

P2004 on Mercedes-Benz: causes and affected engines

P2004 means: intake manifold runner control stuck open (bank 1).^[1][2][3] Mercedes-Benz has 4 documented faults that can trigger it, across 4 engines: OM642, M272/M273, 2.0 CDI (OM640) and M271. Only a diagnosis can confirm the cause on your car.

Documented faults

that can trigger it

Engines

used by Mercedes-Benz, with at least one of them

Mercedes-Benz models

with at least one of these faults

Urgency

Monitor

Reviewed on 31 October 20263 sources How we work

Documented faults in Mercedes-Benz engines that can trigger P2004

Grouped by engine or model, from most to least important. These are faults with the intake flaps and with carbon build-up in the intake: not all of them will necessarily set the code, and only a diagnosis confirms the cause on your car.

OM642

In Clase C W204, Clase E W211, Clase E W212, Clase G W463, Clase M W164, Clase M / GLE W166 and 10 more models

- Critical severityFrequency: CommonIntakeBroken swirl flaps in the intake manifoldYes: the plastic rods of the intake manifold's swirl flaps become brittle and can break at around 100,000-200,000 km. If a loose flap is sucked into a cylinder, it can hit the piston and destroy the engine; this is why removing them preventively is recommended.Repair (garage): €600–€1,200Appears at around 100,000 km

M272/M273

In Clase C W203, Clase C W204, Clase E W211, Clase E W212, Clase M W164, Clase R W251 and 5 more models

- Medium severityFrequency: CommonIntakeBroken flaps and lever in the variable intake manifoldThe M272/M273's variable intake manifold can break the lever or the shafts of the swirl flaps, with loss of power, rough idle and codes P2004-P2006; if a piece comes loose it can end up in the cylinder.
Its page cites code P2004.

2.0 CDI (OM640)

In Clase A W169 and Clase B W245

- Medium severityFrequency: OccasionalInjectionCarbon build-up in the injectorsYes, although with fewer cases than the EGR: the OM640's injectors can build up soot with use, which a specialist German source describes as a cause of expensive repairs. Owner testimonies place it as a secondary problem compared with the EGR or the Autotronic gearbox.

M271

In Clase C W204, Clase E W212 and SLK R172

- Low severityFrequency: CommonIntakeCarbon build-up in the intake on the direct-injection EVO turbo and CGI versionsOn the direct-injection versions (EVO turbo and the short-lived 2003-2005 CGI), the M271 can build up carbon on the intake valves, a problem typical of petrol direct injection. It is treated with mechanical cleaning; good-quality petrol helps prevent it.

Common causes of P2004 on any make

From most to least likely, according to the sources.

1Carbon deposits blocking the flaps, especially on direct-injection engines.^[1][2]
2Faulty flap actuator, motor or solenoid.^[1][2]
3Broken linkage or return spring, or a mechanical seizure in the flap drive.^[1][2]
4Faulty flap position sensor.^[1]

What to check first

The first diagnostic steps, from the most likely and cheapest to check to the most expensive.

1Check whether the actuator and the linkage move the flaps fully when commanded. A seized or broken linkage is a common cause.^[1]
2Inspect the flap shafts for carbon that blocks them in the open position.^[1][2]
3With the diagnostic equipment, command the flaps to move and compare the commanded position with the one the sensor reports.^[1]

Full guide to P2004: symptoms, diagnosis and whether you can drive

Parts related to code P2004 on Mercedes-Benz cars

The parts that most often cause this code. The code points to the circuit, not always the part: diagnose before you buy.

Inlet manifold
- Buy part at Autodoc (affiliate link, opens in a new tab)

Affiliate links: if you buy from these shops, MotorFiable may receive a commission at no cost to you. Check compatibility against the registration plate or VIN before ordering. Affiliate links

Frequently asked questions

Which Mercedes-Benz engines have faults that can trigger P2004?

OM642 (1 fault), M272/M273 (1 fault), 2.0 CDI (OM640) (1 fault) and M271 (1 fault). Each fault has its own page with the affected years and versions, the symptoms and the repair cost.

What does code P2004 mean on a Mercedes-Benz?

Intake manifold runner control stuck open (bank 1). The intake manifold runner flaps of bank 1 (those that create the swirl or “tumble” of the air) are stuck open, or the position feedback shows that they did not close when the control unit commanded it. They normally close at low engine speed to improve low-revs torque and emissions. CarWiki summarises it as an actuator or a control solenoid of the manifold air stuck in the open position, so the air is not regulated as it should be. It is a generic OBD-II code: it means the same on a Mercedes-Benz as on any other make.^[1][2][3]

Can I keep driving with P2004?

Monitor. AutoDTCs rates it as low severity: there is no risk of a breakdown, the car can be driven, but it is worth repairing to recover low-revs torque. CarWiki links it to loss of power, consumption and starting difficulty, so if the car is running worse than usual it should not be set aside.^[1][2]

Sources

Every fact on this page links to its source. If you find an error, let us know.

P2004 – Intake Manifold Runner Control Stuck Open Bank 1 — AutoDTCsAutoDTCs · Technical documentation · published July 2026 · consulted 31 October 2026
OBD DTC Fehlercode P2004 | Ansaugkrümmer-Luftregelungssteller / Magnetventil, Bank 1 – Steller / Magnetventil klemmt offenCarWiki.de · Technical documentation · consulted 31 October 2026 · in German
p2004 Generic DTC: Intake Manifold Runner Control Stuck OpenDTCSearch.com (OBD Solutions) · Technical documentation · consulted 31 October 2026