Technical Description of OBD-II Trouble Code
The IMT Valve in the Intake Manifold is Stuck Open in Bank 2
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that is applicable to many OBD-II vehicles (1996-newer). This includes vehicles from Mercedes Benz, Audi, Chevrolet, GMC, Sprinter, Land Rover, and others. Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration.
A stored code P206E indicates that the powertrain control module (PCM) has detected an intake manifold tuning (IMT) valve that is stuck open in engine bank two. Bank 2 refers to the bank of the engine that does NOT contain the number one cylinder.
Intake manifold tuning is used to regulate and control the intake air as it enters individual manifold ports. The IMT not only regulates the volume of intake air, but also creates a swirling motion. These two factors contribute to more effective fuel atomization. Each intake manifold port has a metal flap, similar to the throttle plate. A single shaft runs through the middle of each port, connecting the metal flaps. The flaps are attached to the shaft and can be turned slightly to open or close them.
The PCM controls the IMT shaft. Some systems use electronic actuators (valves) that operate over vacuum, while others use an electronic motor to move the flaps. The PCM sends the appropriate voltage signal to open or close the IMT valve/s to the desired degree. The PCM monitors the actual valve position to ensure that the system is functioning correctly.
If the PCM detects that the IMT valve is stuck open, it will store a code P206E and illuminate the malfunction indicator lamp (MIL). The MIL may require multiple ignition cycles with a failure to illuminate.
An example of an intake manifold tuning (IMT) valve:
What is the severity of this DTC?
A failure in the IMT system could negatively impact fuel efficiency and, in rare cases, result in hardware being drawn into a combustion chamber. It is important to rectify the conditions that led to the storage of code P206E as quickly as possible.
What are some of the symptoms of the code?
Symptoms of a P206E trouble code may include:
What are some of the common causes of the code?
Possible causes for this code may include:
What are some P206E troubleshooting steps?
To diagnose a code P206E, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and access to vehicle-specific diagnostic information.
Refer to your vehicle information source to find a technical service bulletin (TSB) that matches the vehicle’s year, make, and model, as well as the engine size, stored codes, and exhibited symptoms. If available, the TSB could provide helpful diagnostic information.
Use the scanner connected to the vehicle diagnostic connector to retrieve all stored codes and relevant freeze frame data. It is recommended to write down this information before clearing the codes, and 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 more difficult to diagnose. In such cases, the conditions that 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 in the diagnosis will involve searching your vehicle information source for diagnostic flowcharts, connector pin-out charts, connector face views, and component testing procedures/specifications.
Step 1
Use your vehicle diagnostic information source and the DVOM to test the voltage, ground, and signal circuits at the appropriate IMT valve.
Step 2
Use the DVOM to test the appropriate IMT valve according to the manufacturer’s specifications. Components that do not test within the maximum allowable parameters should be considered defective.
Step 3
If the IMT valve is functioning properly, use the DVOM to test the input and output signal circuits from the fuse panel and PCM. Disconnect all controllers before using the DVOM for testing.
