P206E Intake Manifold Tuning (IMT) Valve Stuck Open Bank 2
OBD-II Trouble Code Technical Description
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总裁俱乐部appIntake Manifold Tuning (IMT) Valve Stuck Open 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 P206E means that the powertrain control module (PCM) has detected an intake manifold tuning (IMT) valve that is stuck open 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.
总裁俱乐部appIf the PCM detects that the IMT valve is stuck open, a code P206E 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?
总裁俱乐部appIMT 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 P206E being stored should be rectified as quickly as possible.
What are some of the symptoms of the code?
Symptoms of a P206E trouble code may include:
- Diminished fuel efficiency
- Reduced engine performance
- Lean or rich exhaust codes
- No symptoms at all may be exhibited
What are some of the common causes of the code?
总裁俱乐部appCauses 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 error
What are some P206E 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 P206E.
总裁俱乐部appYou 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 information source for diagnostic flow-charts, connector pin-out charts, connector face views, and component testing procedures/specifications.
总裁俱乐部appUse your source of vehicle diagnostic information and the DVOM to test voltage, ground, and signal circuits at the appropriate IMT valve.
总裁俱乐部appUse the DVOM to test the appropriate IMT valve according to manufacturer specifications. Components which do not test within maximum allowable parameters should be considered defective.
总裁俱乐部appIf the IMT valve is functional, use the DVOM to test input and output signal circuits from the fuse panel, and PCM. Disconnect all controllers prior to using the DVOM for testing.
- Failed IMT valves, linkages, and bushings are typically at the root of IMT related codes.
Related DTC Discussions
- 2011 Mercedes gl350 obd code P206E
Im trying to figure this code out. A brief search says its intake manifold flaps. A more intense search says mb specific having to do with a/t controller. Anybody know if a regular obd2 scanner can even read these proper?...
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