Technical Description of OBD-II Trouble Code
The intake manifold runner control for Bank 1 is stuck closed.
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code that applies to all vehicles manufactured from 1996 onwards (Nissan, Honda, Infiniti, Ford, Dodge, Acura, Toyota, etc.). While it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
If your vehicle equipped with OBD II has stored a code P2006, it means that the powertrain control module (PCM) has detected that the intake manifold air control (IMRC) actuator for engine bank one is stuck in the closed position. Bank 1 refers to the engine bank that contains the number one cylinder, indicating that the malfunction is related to that bank.
The PCM controls the IMRC system, which is responsible for managing and fine-tuning the airflow as it enters the lower intake manifold, cylinder heads, and combustion chambers. The IMRC system uses carefully shaped metal flaps that fit snugly into the intake port of each cylinder. These flaps are opened and closed by an electronic runner control solenoid. The flaps are attached to a thin metal rod that extends through the center of each intake port. If one of the flaps is stuck or binding, all of the flaps will be inoperative. The IMRC actuator is typically attached to the rod using a mechanical arm or a gear. Some models use a vacuum diaphragm to operate the actuator, with the PCM controlling an electronic solenoid that regulates intake vacuum to the IMRC actuator.
The swirling effect created by channeling and restricting the airflow as it enters the engine helps to atomize the air/fuel mixture more thoroughly. This more complete atomization reduces exhaust emissions, improves fuel efficiency, and optimizes engine performance.
Different manufacturers use different IMRC methods. Consult your vehicle information source (such as All Data DIY) for details about the specific IMRC system in your vehicle. Typically, the IMRC runners are partially closed during starting and idling situations, and fully opened when the throttle plate is opened.
To ensure that the IMRC system is functioning properly, the PCM monitors input signals from various sensors, including the IMRC runner position sensor, manifold absolute pressure (MAP) sensor, manifold air temperature sensor, intake air temperature sensor, throttle position sensor, oxygen sensors, and mass airflow (MAF) sensor.
The PCM monitors the actual position of the runner flaps and adjusts them based on engine drivability data. If the PCM does not see the expected change in MAP or manifold air temperature with the desired repositioning of the flaps (by the IMRC actuator), it will store a code P2006. In some models, multiple ignition cycles with an IMRC actuator failure are required for the malfunction indicator lamp (MIL) to illuminate.
Symptoms
Symptoms of a P2006 code may include:
Causes
Possible causes for this engine code include:
Diagnostic and Repair Procedures
When attempting to diagnose a code P2006, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable vehicle information source. It is advisable to check for any relevant technical service bulletins (TSB) that may provide information about the symptoms, stored codes, and specific make and model of the vehicle before starting the diagnosis. If a related TSB is found, it can often assist in diagnosing the code.
A visual inspection of the system wiring and connector faces is a good starting point for any diagnosis. In this case, pay attention to the IMRC actuator connectors, as they are prone to corrosion, which can cause an open circuit.
Next, connect the scanner to the vehicle diagnostic connector and retrieve all stored codes and freeze frame data. It is recommended to write down this information in case the code is intermittent. Clear the codes and test-drive the vehicle to see if the code is reset.
If the code is reset, gain access to the IMRC actuator solenoid and IMRC runner position sensor. Consult your vehicle information source for testing specifications for these components. Use the DVOM to perform a resistance test on the solenoid and sensor. If either of these parts does not comply with the specifications, replace it and retest the system.
Before testing circuit resistance with the DVOM, disconnect all related controllers to prevent PCM damage. If the actuator and sensor resistance are within the manufacturer’s specifications, use the DVOM to test resistance and continuity on all system circuits. Repair or replace any shorted or open circuits as necessary.
Additional diagnostic notes:
