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P2004 – What Does It Mean and How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.

Definition

If you get an OBD-II scanner error code P2004 it means that the Intake Manifold Runner Control (IMRC) actuator is stuck in the open position.

Meaning

The OBD – II code P2004 represents that the intake manifold runner control is stuck in the open position on Bank 1. The Powertrain Control Module (PCM) furnishes the IMRC with information about current driving conditions. IMRC uses this information to adjust the allowable airflow in the intake system.

The PCM receives information from the IMRC solenoid valve, the Barometric Pressure (BARO) sensor, and the Mass Air Flow (MAF) sensor to determine the correct position of the IMRC butterfly valve plate. These plates are then opened and closed to allow or restrict air intake to the air intake system.

At high rpm, the IMRC butterfly valve plate will open to allow air to enter the intake system, while at low rpm, the IMRC butterfly valve plate will close to restrict airflow into the intake system. If the PCM finds that the voltage readings of the IMRC solenoid valve, BARO sensor, and the MAF sensor reflect that the IMRC throttle position is incorrect, it will reflect the diagnostic trouble code P2004.

Causes

The possible causes for the error code P2004 include:

  • Faulty IMRC solenoid 
  • The IMRC solenoid is short, broken, or frayed
  • Corroded IMRC solenoid connector 
  • Loose or damaged IMRC butterfly valve plate screw 
  • Broken or damaged IMRC butterfly valve plate 
  • IMRC butterfly valve plate disconnected from IMRC actuator 
  • Vacuum filter electrically clogged 
  • Vacuum line disconnected or damaged 
  • Carbon accumulation on the butterfly valve plate 
  • IMRC Exhaust Gas Recirculation (EGR) valve trouble code saved by PCM 
  • MAF sensor error code has been stored by PCM
  • BARO error code of PCM has been stored by PCM

Symptoms

  • Reduction in engine torque
  • Decrease in fuel economy
  • The engine may surge/spark
  • The vehicle will run rough
  • Check Engine Light on
  • Check Engine Light flashing

Diagnosis

For the correct diagnosis and solution of the error code P2004, you should follow the steps mentioned beneath:

  • Use the OBD-II scanner to collect the freeze frame data and any error codes that have been stored by the PCM (if the error codes for the EGR valve, MAF sensor, and BARO sensor are already stored by the PCM, then they should be diagnosed and repaired first)
  • Perform a visual inspection of all wiring to detect shorts, breaks, and fray
  • Repair or replace any shorted, frayed, or broken wiring
  • Perform the IMRC electromagnetic visual inspection for corrosion and damage 
  • Repair or replace any corroded or damaged connectors 
  • Inspect hoses and vacuum line
  • Repair or replace any loose or damaged vacuum lines or hoses
  • Check the IMRC butterfly valve plates for proper and/or broken connections
  • Check the EGR valve for excessive carbon buildup 
  • Clear the codes and retest to see if the P2004 trouble code return
  • Use the scan tool to check the IMRC solenoid: Open and close the IMRC solenoid with the scanner. If the IMRC solenoid valve does not respond, the solenoid valve needs to be replaced.

Common Mistakes

  • Wrong diagnosis and replacement of IMRC solenoid 
  • Wrong diagnosis and replacement of IMRC butterfly valve plates
  • Watch out for damaged or disconnected vacuum lines 
  • Find IMRC connector and wiring 
  • Replace valve plates IMRC throttle valve when the problem is they are not connected properly
  • Ignoring diagnosis and repairing other EGR valves, MAF sensor and/or BARO trouble codes before making any repairs

How Serious Is This Code?

If the IMRC throttle valve plate hardware becomes loose and falls inside the engine, the P2004 trouble code can become very serious. If this happens, the engine can be seriously damaged. It is important to check and correct the P2004 trouble code as soon as possible.

What repairs can fix the code?

Below mentioned are the few ways with the help of which you will be able to fix the OBD Code P2004

  • IMRC solenoid valve replacement 
  • Repair or replace short-circuited, broken, or worn IMRC solenoid valve wiring
  • Repair or replace short-circuited or open IMRC solenoid valve circuit 
  • Repair or replace corroded IMRC solenoid valve connectors
  • If necessary, repair and/or replace IMRC butterfly valve plate hardware 
  • Replace IMRC butterfly valve plate (for this, the intake manifold assembly needs to be replaced) 
  • EGR valve, MAF Diagnosis and repair of sensor and/or BARO fault code (if any)

Related codes

  • 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
  • P2012: IMRC Circuit Low Bank 2
  • P2013: IMRC Circuit High Bank 2

Conclusion

The OBD-II scanner error code P2004 can cause serious damage to most engine components; the biggest danger of this error code is poor performance and fuel efficiency. If all cylinder valves are connected to the cylinder head, the engine may not work at all. A problem with one cylinder may cause all cylinders to fail to ignite. If this happens, the engine can be seriously damaged. It is important to check and correct the P2004 trouble code as soon as possible.

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