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ItalianoP2004 Intake Manifold Runner Control Stuck Open (Bank 1)
The intake manifold runner control (swirl or tumble flaps) changes the air path in the intake manifold to improve air motion at low engine speed. The ECU compares the commanded flap position with the position feedback and sets P2004 when the flaps remain open while commanded closed.
Common causes
- Carbon build-up seizing the flaps or shaft
- Faulty flap actuator, electric or vacuum-operated
- Broken linkage between the actuator and the flap shaft
- Faulty position sensor
- Vacuum leaks or wiring faults
Typical symptoms
- Check engine light (MIL) on
- Rough idle or reduced low-speed torque
- Higher emissions
- Reduced power or limp mode on some vehicles
P2004 and NuoVolta
If the swirl or tumble flaps have been removed or blanked for off-road or motorsport use, where permitted by law, the NuoVolta Flaps / Swirl Removal solution adjusts the ECU calibration and the DTC removal feature can disable this code. On engines with flaps still fitted, inspect them, as loose or broken flaps can damage the engine on some designs.
Diagnose and repair real faults first. Removing or disabling emission systems is only permitted where allowed by law, for example for off-road or motorsport use.