Where is the Audi's intake manifold stuck in the open position?
2 Answers
Audi's intake manifold stuck in the open position is caused by: a water pump issue, where the vacuum system of the water pump is damaged, affecting the intake manifold's flap. The variable intake manifold stuck in the open position is determined by the engine's ECU based on data stored in the memory, reflecting a fault code. The reasons for this are either a damaged position sensor or an intake manifold fault, which can be repaired at a 4S shop. Function of the intake manifold: For carburetor or throttle body fuel injection engines, the intake manifold refers to the intake passage from the carburetor or throttle body to the cylinder head's intake port. Its function is to distribute the air-fuel mixture from the carburetor or throttle body to each cylinder's intake port. Advantages of plastic intake manifolds: Lower cost and lighter weight. Additionally, since PA has lower thermal conductivity than aluminum, the fuel injectors and incoming air temperature are lower. This not only improves hot start performance and increases engine power and torque but also helps avoid heat loss in the pipe during cold starts, speeding up the increase in gas temperature. Moreover, the smooth inner wall of the plastic intake manifold reduces air flow resistance, thereby enhancing engine performance.
I've been driving an Audi A4 for several years, and last time this warning popped up on the dashboard, it really startled me. The intake manifold is stuck in the open position, which basically means the moving valve inside the manifold isn't closing. It usually gets stuck in the manifold itself, like when the flap is clogged with carbon deposits or sludge. The location is right at the front of the engine, near the intake part of the engine—that thick pipe you can see as soon as you lift the hood. If it's stuck open, the intake remains open, disrupting airflow and making the engine 'breathe' poorly. Acceleration feels sluggish, the car accelerates slowly, and idle is shaky, as if it's half-asleep. I suggest not pushing through it—first, check the external connection points of the manifold with a flashlight. Loose vacuum hoses or actuator connectors can also cause this issue. If left unaddressed, it can waste fuel and, worse, damage the engine core over time. It's best to take it to a professional shop right away to clean the carbon deposits or replace small parts—it’s both cost-effective and safer.
