what does cause P2004 CODE an were is it. My car has a manual transmission.
Diagnostic trouble code P2004 signifies a problem with a segment of the engine’s air intake and control system, technically known as the intake manifold runner control (IMRC). In practical terms, the code means that the engine is not getting the right amount of air to perform efficiently. There are quite a few sensors, as well as mechanical components, that can account for this fault.
Here is a list of some of the possible root causes for code P2004: a defective IMRC solenoid; IMRC solenoid wiring that has shorts, has breaks, or is frayed; IMRC solenoid circuitry that has shorted or is open; an IMRC solenoid connector that is corroded; IMRC butterfly valve plate screws that are loose or broken; broken IMRC butterfly valve plates; IMRC butterfly valves plates that have disconnected from the IMRC actuator; a clogged vacuum control solenoid vacuum filter; debris in the vacuum control solenoid; vacuum lines that are disconnected or broken; or carbon buildup on the IMRC butterfly valve plates. If none of the aforementioned defects account for the fault, there are three other systems that should then be evaluated as well. Check for trouble codes that have been stored by the powertrain control module (PCM) in relation to the exhaust gas recirculation (EGR) valve, the mass airflow (MAF) sensor, and the barometric pressure (BARO) sensor.
If the fault is due to the mechanical butterfly valve in the intake coming loose, that could result in big problems as this is a metal part that could potentially get sucked into the engine causing further damage. Consequently, this is not an issue that can be put off in terms of getting the problem diagnosed and repaired. Also, while the fault exists, you are likely getting lower gas mileage, which of course is costly.
A certified technician, such as one from YourMechanic, can evaluate the fault during a Check Engine Light inspection and let you know which component(s) has failed and then get the vehicle repaired for you.