P206F Intake Manifold Tuning (IMT) Valve Stuck Closed Bank 2
OBD-II Trouble Code Technical Description
Intake Manifold Tuning (IMT) Valve Stuck Closed Bank 2
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code and applies to many OBD-II vehicles (1996-newer). That may include but is not limited to vehicles from Mercedes Benz, Audi, Chevrolet, GMC, Sprinter, Land Rover, etc. Although generic, the exact repair steps may vary depending on year, make, model and powertrain configuration.
A stored code P206F means that the powertrain control module (PCM) has detected an intake manifold tuning (IMT) valve that is stuck closed for engine bank two. Bank 2 refers to the bank of the engine which does NOT contain the number one cylinder.
Intake manifold tuning is used to restrict and control intake air as it enters individual manifold ports. Not only is the volume of intake air regulated by the IMT, a swirling motion is also created. These two factors aid in more effective fuel atomization. Each intake manifold port is outfitted with a metal flap; not unlike the throttle plate. A single shaft runs from one end of the manifold (per engine bank) to the other and through the middle of each port. The metal flaps are attached to the shaft which will be turned (slightly) to effect opening and closing of the flaps.
The IMT shaft is actuated by the PCM. Some systems use an electronic over vacuum system of actuators (valves). Other systems use an electronic motor to effect flap movement. The PCM sends the appropriate voltage signal and the IMT valve opens and closes the valve/s to the desired degree. The PCM monitors actual valve position to determine if the system is functioning as intended.
If the PCM detects that the IMT valve is stuck closed, a code P206F will be stored and a malfunction indicator lamp (MIL) illuminated. MIL illumination may require multiple ignition cycles with a failure.
An example of an intake manifold tuning (IMT) valve:
What is the severity of this DTC?
IMT system failure could adversely affect fuel efficiency and, in rare cases, involve hardware being drawn into a combustion chamber. Conditions which led to a code P206F being stored should be rectified as quickly as possible.
What are some of the symptoms of the code?
Symptoms of a P206F trouble code may include:
Diminished fuel efficiency Reduced engine performance Lean or rich exhaust codes No symptoms at all may be exhibitedWhat are some of the common causes of the code?
Causes for this code may include:
Binding or loose IMT flaps Defective IMT actuator (valve) Vacuum leak Open or shorted wiring or connectors Faulty PCM or a PCM programming errorWhat are some P206F troubleshooting steps?
A diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of vehicle specific diagnostic information will be required to diagnose a code P206F.
You may use your source of vehicle information to locate a technical service bulletin (TSB) that matches the vehicle year, make, and model; as well as the engine size, code/s stored, and symptoms exhibited. If you find one, it could yield helpful diagnostic information.
Use the scanner (connected to the vehicle diagnostic connector) to retrieve all stored codes and pertinent freeze frame data. It is a good idea to write this information down before clearing the codes then test-drive the vehicle until the PCM either enters readiness mode or the code is reset.
If the PCM enters readiness mode at this time, the code is intermittent and may be much more difficult to diagnose. If this is the case, the conditions which contributed to the code being stored may need to worsen before an accurate diagnosis can be made.
If the code is immediately reset, the next step of your diagnosis will require that you search your vehicle i
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