P2004
Intake Manifold Runner Control Stuck Open (Bank 1)
- Severity
- Medium
- Driving
- Drivable — book it in
The intake manifold runner flaps on bank 1 are stuck open. These flaps change how air swirls into the cylinders - closed at low speed to increase turbulence and improve combustion, open higher up so the engine can breathe. Stuck open, the engine loses low-speed torque and may run roughly or smoke at idle.
Possible causes
- CommonCarbon build-up seizing the runner flaps or their linkage
- CommonFailed actuator motor or vacuum diaphragm
- CommonSplit, perished or disconnected vacuum hose
- CommonBroken linkage or a detached flap
- PossibleCorroded connector or damaged wiring
- PossibleFailed position sensor giving a false reading
What you might notice
- Loss of low-speed torque or flat top-end power
- Rough idle
- Hesitation
- Worse fuel economy
- Smoke on a diesel
- Check engine light on
What to check, in order
- Check the vacuum hoses first on a vacuum-operated system - a split or disconnected hose is the most common cause and the cheapest to fix.
- Check the flaps and linkage move freely. Carbon seizing them is very common on a diesel used for short journeys, and cleaning is often the whole repair.
- Watch commanded against actual runner position on the live data screen through a sweep.
- Inspect the connector for corrosion and the actuator for damage.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Fuel, air metering and auxiliary emission controls
P2000P2001P2002P2003P2004P2005P2006P2007P2008P2009P2010P2011P2012P2013P2014P2015P2016P2017P2018P2019P2020P2021P2022P2023P2024P2025P2026P2027P2028P2029P2030P2031P2032P2033P2034P2035P2036P2037P2038P2039P2040P2041P2042P2043P2044P2045P2046P2047P2048P2049P2050P2051P2052P2053P2054P2055P2056P2057P2058P2059P2060P2061P2062P2063P2064P2065P2066P2067P2068P2069P2070P2071P2075P2076P2077P2078P2079P2080P2081P2082P2083P2084P2085P2086P2087P2088P2089P2090P2091P2092P2093P2094P2095P2096P2097P2098P2099