P2012 code definition
Intake Manifold Runner Control (IMRC) Circuit Low Bank 2
Related Trouble Codes:
- P2004: IMRC Stuck Open Bank 1
- P2005: IMRC Stuck Open Bank 2
- P2006: IMRC Stuck Closed Bank 1
- P2007: IMRC Stuck Closed Bank 2
- P2008: IMRC Circuit Open Bank 1
- P2009: IMRC Circuit Low Bank 1
- P2010: IMRC Circuit High Bank 1
- P2011: IMRC Circuit Open Bank 2
- P2013: IMRC Circuit High Bank 2
- P2014: Intake Manifold Runner Pos Sensor/Switch Circ Bank 1
- P2015: Intake Manifold Runner Pos Sensor/Switch Circ Range/Perf Bank 1
- P2016: Intake Manifold Runner Pos Sensor/Switch Circ Low Bank 1
- P2017: Intake Manifold Runner Pos Sensor/Switch Circ High Bank 1
- P2018: Intake Manifold Runner Pos Sensor/Switch Circ Interm Bank 1
- P2019: Intake Manifold Runner Pos Sensor/Switch Circ Bank 2
- P2020: Intake Manifold Runner Pos Sensor/Switch Cir Range/Perf Bank 2
- P2021: Intake Manifold Runner Pos Sensor/Switch Circ Low Bank 2
- P2022: Intake Manifold Runner Pos Sensor/Switch Circ High Bank 2
- P2023: Intake Manifold Runner Pos Sensor/Switch Circ Interm Bank 2
What the P2012 code means
The P2012 diagnostic trouble code indicates that there is an issue with the intake manifold runner control (IMRC) circuit in Bank 2.
The purpose of the IMRC is to regulate the amount of airflow that is permitted into the intake system, using information it has received from the Powertrain Control Module (PCM) regarding current driving conditions. This improves the fuel/air mixture, and reduces harmful emissions. The IMRC has a vacuum actuator, electric solenoid, butterfly valve plates, air passageways to each cylinder, linkage rods connected to the intake manifold butterfly plate lever, and return springs that hold the butterfly valve plates open. The IMRC butterfly valve plates, that look like flaps, open and close to allow or restrict airflow into the intake. The PCM uses information it receives from the IMRC, mass airflow (MAF) sensor and barometric (BARO) sensor to make a determination as to the proper position of the IMRC butterfly valve plates. The IMRC butterfly valves will open at higher speeds/higher RPM, and close at lower speeds/lower RPM. If voltage readings from the IMRC solenoid, MAF sensor, and/or BARO sensor demonstrate that the butterfly valve plates are not in the proper position, the PCM will store the P2012 trouble code.
What causes the P2012 code?
- IMRC solenoid that is defective
- IMRC solenoid wiring that has shorts, breaks, or is frayed.
- IMRC solenoid circuitry that has shorted or is open
- IMRC solenoid connector that is corroded
- IMRC butterfly valve plate screws that are loose or broken
- IMRC butterfly valve plates that are broken
- IMRC butterfly valves plates that have disconnected from the IMRC actuator
- Vacuum control solenoid vacuum filter that is clogged
- Debris in the vacuum control solenoid
- Vacuum lines that are disconnected or broken
- Carbon buildup on the IMRC butterfly valve plates
- Exhaust Gas Recirculation (EGR) valve trouble codes that have been stored by the PCM
- MAF sensor trouble codes that have been stored by the PCM
- BARO sensor trouble codes that have been stored by the PCM
What are the symptoms of the P2012 code?
- Decrease in fuel economy
- Decrease in low end engine torque
- The engine may surge/sputter
- The vehicle will run rough
- Check Engine/Service Engine Soon Light on
- Check Engine/Service Engine Soon light flashing
How does a mechanic diagnose the P2012 code?
- Uses an OBD-II scanner to collect freeze frame data and any trouble codes that have been stored by the PCM (if trouble codes for the EGR valve, MAF sensor, and/or BARO sensor have been stored by the PCM, they should be diagnosed and repaired first)
- Completes a visual inspection of all wiring for shorts, breaks, and frays
- Repairs or replaces any wiring that has shorted, is frayed, or broken
- Completes a visual inspection of the IMRC solenoid for corrosion and damage
- Repairs or replaces any of the connectors that are corroded or damaged
- Inspects the vacuum lines and hoses
- Repairs or replaces any of the vacuum lines or hoses that are loose or damaged
- Inspects the IMRC butterfly valve plates for proper connection and/or breaks
- Inspects the EGR valve for excessive carbon buildup (this carbon buildup could get onto the IMRC solenoid and render it defective)
- Clears the codes and retests to see if the P2012 trouble code returns
- Uses the scan tool to test the IMRC solenoid:
Open and close the IMRC solenoid using the scanner. If the IMRC solenoid does not respond, the solenoid will need to be replaced.
Common mistakes when diagnosing the P2012 code
- Misdiagnosing and replacing the IMRC solenoid
- Misdiagnosing and replacing the IMRC butterfly valve plates
- Overlooking damaged or disconnected vacuum lines
- Overlooking IMRC solenoid connector and wiring
- Replacing the IMRC butterfly valve plates when the problem was that they were not connected properly.
- Neglecting to diagnose and repair other EGR valve, MAF sensor, and/or BARO trouble codes before making any repairs for the P2012 trouble code.
How serious is the P2012 code?
If the IMRC butterfly valve plate hardware are loose and fall off into the engine, this could cause severe internal engine damage. For this reason this code is considered serious. It should be addressed as soon as possible.
What repairs can fix the P2012 code?
- Replacing the IMRC solenoid
- Repairing or replacing IMRC solenoid wiring that is has shorts, breaks or is frayed
- Repairing or replacing IMRC solenoid circuitry that has shorted or is open
- Repairing or replacing IMRC solenoid connector that is corroded
- Repairing and/or replacing IMRC butterfly valve plate hardware, if necessary
- Repairing or replacing loose or damaged vacuum lines
- Replacing IMRC butterfly valve plates (in order to do this, the intake manifold assembly will need to be replaced)
If EGR valve, MAF sensor, and/or BARO trouble codes are present, diagnose and repair.
Be sure to check the connection of the IMRC butterfly valve plates to the IMRC actuator. If there is a loose connection, this is a simple and quick fix to resolve this trouble code. Also, it is common for carbon buildup to form on the IMRC, which causes poor operation. However, this happens inside the intake and can not be seen. Without having the all of the necessary tools to diagnose this trouble code, it will be necessary to replace the entire intake assembly.
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