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P2021 is a diagnostic trouble code (DTC) for "Intake Manifold Runner Position Sensor/Switch Circuit Low Bank 2". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
Intake Manifold Runner Position Sensor/Switch Circuit Low Bank 2
It should be noted that this code can have a different description if the vehicle has a diesel engine. If that is the case, the definition would be “Rail Pressure Monitoring VIA Pressure Control Valve, pressure low”. Not as common as the gas code definition, but still in use on some vehicles.
Circuit Low Bank 2 is stating the circuit has lower value than the PCM (powertrain control module) expects. The resistance or voltage in the sensor changes as the valve position changes.
There is typically an actuator or solenoid that redirects the path of air traveling through the intake manifold to the cylinders. The changing intake runner length is used to optimize air flow through the intake manifold as RPM (revolutions per minute) change.
This code is set when the PCM sensor monitoring the intake runner valve position is not in the expected position. Most often the computer is watching a changing resistance or voltage value that increases or decreases depending on the valves position.
Usually there is a drivability concern noticed by the owner. The vehicle can exhibit a variety of symptoms depending on the type of system being used:
The technician will first connect a scanner to the vehicle to either command the system on or simply to monitor the system data.
Often times a handheld vacuum pump will be used to test one or more vacuum operated actuators. If the system is actuated electrically then the components will often be referred to as a solenoid or motor.
Regardless of the technology, the technician is monitoring the intake to see if the internal valve is being turned by the solenoid, actuator or motor. This can be accomplished by commanding the system on with the scanner or driving the vehicle under the conditions necessary to activate the system and watch the scan tool data.
Many times it is necessary to disassemble the intake to see if the intake runner valve is stuck.
These systems are fairly simple in their design and function, although the rationale for their use is often misunderstood. For this reason a mechanic will often miss other problems with the motor that will affect the operation of this system.
Other than the inconvenience of erratic drivability symptoms, problems with this system will not likely cause any permanent damage to the motor. Although the symptoms will likely be noticeable enough to force the owner to seek a repair shop sooner than later. Driving a vehicle with this system impaired will most likely be frustrating.
Usually it is a broken diaphragm inside a vacuum controlled actuator that needs to be replaced. However, other possibilities are:
Each manufacturer utilizes different strategies when designing a VIM system (variable intake manifold). For this reason terminology will differ between manufacturers. This particular code is for bank 2. This indicates there are likely two sensors for this engine. Bank 2 would be the sensor on the intake runner that supplies air to the bank of cylinders not including number one cylinder.
This code specifically monitors the variable intake manifold valve position sensor. The sensor is used by the PCM to know what position the VIM valve is in. If this valve is not in the position the PCM is expecting for the present engine conditions, code P2021 will be set. It should be noted, if the motor has only one bank of cylinders, this code will not be utilized for that particular vehicle.
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