Air intakeGeneric OBD-II codeUrgency: Monitor
Code P2004: intake runners stuck open (bank 1)
P2004 means: intake manifold runner control stuck open (bank 1).[1][2][3] 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.[1][2]
What code P2004 means
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.[1][2]
AutoDTCs recommends confirming before testing whether the engine uses a vacuum actuator or an electric one, because the tests are different. P2005 is the same warning on bank 2. It is a generic code of the OBD-II standard (it starts with P2), with the same definition on any brand.[1][4][5][6]
Original definition (SAE J2012): Intake Manifold Runner Control Stuck Open Bank 1[1][2][3]
Codes from the same family
They indicate the same problem in a specific cylinder, bank or sensor. Causes, symptoms and diagnosis are those on this page.
Causes of P2004 and its family
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]
- 5Leak in the actuator diaphragm, on systems that work by vacuum.[1]
- 6Damaged wiring or connectors.[1][2]
- 7Control unit fault, according to CarWiki.[2]
Symptoms
- Engine fault warning light on.[1][2]Engine warning light: faults that cause it
- Slightly irregular idle.[1][2]
- Less torque at low revs: the car feels sluggish when pulling away from idle.[1][2]Less power: faults that cause it
- Hesitation just when accelerating from idle, or irregular running.[1][2]Jerking: faults that cause it
- A small rise in consumption.[1][2]Uses more fuel: faults that cause it
- Difficulty starting, according to CarWiki.[2]Hard to start: faults that cause it
How to diagnose P2004
In order: 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]
- 4On vacuum systems, check that the actuator holds vacuum and that the vacuum supply is intact.[1]
- 5Check the circuits of the actuator and the position sensor: breaks, short circuits or corrosion.[1][2]
- 6Clean the flaps or replace the actuator, or the whole manifold if the flaps do not close. If there is no mechanical cause, check whether there is a control unit software update.[1][2]
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]
Parts related to code P2004
The parts that most often cause this code. The code points to the circuit, not always the part: diagnose before you buy.
Inlet manifold
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Documented faults related to P2004
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Faults in which this code appears
Intake flaps (swirl flaps): the most serious faults by engine and car
- Critical severityFrequency: Very frequentBMW M47Intake swirl flap breakage (swirl flaps)Yes: the common rail versions of the M47 (built since 2001) have flaps in the intake manifold that, with diesel soot and heat cycles, can break and be sucked into the cylinder, with a risk of serious damage to the piston, cylinder head and valves.
- Critical severityFrequency: CommonBMW N47Broken intake manifold swirl flapsYes: the N47's intake manifold has plastic swirl flaps that, with diesel soot and the passing years, can crack, come loose and be sucked into the cylinder, with a risk of seriously damaging the piston, cylinder head and valves.
- Critical severityFrequency: CommonBMW M57Broken intake swirl flapsYes: most automatic M57 and M57TU engines (330d, 530d, 535d, 730d, X3 3.0d and so on) have six metal flaps in the intake manifold that can seize, come loose and wreck a cylinder. The E53 X5 3.0d and the manual gearboxes of the first 330d/530d are free of them, according to a specialist workshop.
- Critical severityFrequency: CommonOM642Broken 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
Carbon build-up in the intake: the most serious faults by engine and car
- Medium severityFrequency: Very frequent2.0 TSI / TFSICarbon build-up on the intake valvesBecause the fuel is injected directly into the cylinder, no petrol washes over the intake valves, so oil residue and soot build up and, over the years, restrict airflow and affect engine response.
- Medium severityFrequency: Common1.6 HDiLeaks at the injector washers and carbon build-up in the cylinder headIt is common for the copper washers of the 1.6 HDi injectors to stop sealing: the engine blows gases, carbon forms around the injector and soot gets into the oil. It is cheap to repair, but if left it contaminates the oil and is one of the causes of turbo failure.Repair (garage): €110–€310
- Medium severityFrequency: Common1.6 GDI / T-GDICarbon build-up on the intake valvesBeing pure direct injection, with no port injectors to wash the valves, the 1.6 GDI and T-GDI build up intake carbon with mileage: unstable idle, jerking or loss of power. A design trait of all direct injection, not a manufacturing fault.
- Medium severityFrequency: CommonMZR-CDCarbon on the injectors, EGR valve and intakeUrban use and short journeys encourage carbon to build up on the injectors, EGR valve and intake of the MZR-CD, with loss of power and jerking; documented on the Mazda6 and Mazda3, on both the 2.0 and the 2.2.
P2004 by make
Documented faults that can trigger P2004 in each make's engines and cars.
Frequently asked questions
What are the intake manifold flaps for?
According to AutoDTCs, they normally close at low engine speed to improve low-revs torque and emissions. When they stay open, the engine loses that effect.[1]
Can I keep driving with P2004?
AutoDTCs says yes, and that it should be fixed soon: it is not a fault that leaves the car stranded, but the car will have less torque at low revs and may feel sluggish when accelerating from standstill.[1]
Does the intake manifold need replacing?
Not first. AutoDTCs advises checking the actuator and linkage movement, carbon on the shafts and the electrical circuits first, and replacing the actuator or the manifold only if the flaps do not close after cleaning.[1]
And if the code is P2005?
It is the same problem on bank 2: manifold flaps stuck open. It is diagnosed in the same way.[4][5]
Will I pass the MOT with code P2004?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[7]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
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
- P2005 – Intake Manifold Runner Control Stuck Open Bank 2 — AutoDTCsAutoDTCs · Technical documentation · consulted 31 October 2026
- p2005 Generic DTC: Intake Manifold Runner Control Stuck OpenDTCSearch.com (OBD Solutions) · Technical documentation · consulted 31 October 2026
- On-board diagnosticsWikipedia · Other source · consulted 31 October 2026
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish