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P0066 Code – What Does It Mean & 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.


The DTC code P0066 is related to a malfunction with the Absolute Manifold Pressure MAP sensor and Air Mass Sensor Correlation. In vehicles fitted with OBD II systems, which monitor the performance of individual components like MAP and air mass sensors, this code is most likely to be detected.


The P0066 code indicates that the electronic control module (ECM) has detected an inconsistency between the readings of the MAP sensor and the air mass sensor. The pressure of the intake manifold is measured with a MAP sensor, as are the air mass sensors that measure how much air enters the engine.


The P0066 DTC code may be brought on by a number of probable factors, including:

  • Faulty MAP sensor: A defective or malfunctioning MAP sensor may give false data, resulting in the code.
  • Malfunctioning air mass sensor: An air mass sensor that has failed or is malfunctioning may give inconsistent readings, setting off the code.
  • Wire problems: Corroded, damaged, or loose wire and connectors connected to the sensors might prevent them from communicating, which can result in the code.
  • Leaks in the intake manifold may alter the readings from the MAP sensor, which might result in the code.
  • ECM malfunction: On occasion, a malfunctioning ECM may identify a correlation problem wrongly and set off the code.


Common symptoms associated with the P0066 DTC code may include:

  • Illuminated check engine light (MIL)
  • Decreased engine performance
  • Rough idling or stalling
  • Reduced fuel efficiency
  • Poor acceleration


The following steps will be usually performed by a skilled mechanic in order to correctly identify the P0066 code: 

  • Use diagnostic scanners to retrieve the particular trouble code for each problem. 
  • Check for MAP and air mass sensors’ wires and connectors. 
  • Manually test the MAP and air mass sensors to make sure they work properly. 
  • Check to see if there’s any leakage from the intake manifold. 
  • Investigate the functionality and potential communication problems of the ECM.

Common mistakes

In the context of the P0066 DTC code, there are several common errors that need to be avoided:

  • Lack of taking into account other related codes or issues that can occur at the same time. 
  • In order to confirm their failure, the MAP or air mass sensors must be replaced without proper testing. 
  • Ignoring wiring and connector problems that could be the cause of this correlation problem.

How serious is this?

However, the P0066 code is not to be taken lightly given its possible immediate severe consequences. If this issue was not addressed, it could lead to a reduction in engine performance, less fuel efficiency, and a possible impact on the remainder of the components over time. To avoid any additional complications, the code should be addressed in a timely manner.

What repairs can fix the code?

repair manuals

To resolve the P0066 DTC code, potential repairs may include:

  • Replacing a faulty MAP sensor or air mass sensor if they fail to test.
  • Repairing or replacing damaged wiring and connectors related to the sensors.
  • Addressing any intake manifold leaks.
  • In rare cases, replacing a faulty ECM, if diagnosed as the cause.

Related codes

Other related codes that may be encountered alongside or instead of P0066 include:

  • P0067: Air-Assisted Injector Control Circuit High
  • P0068: MAP/MAF – Throttle Position Correlation
  • P0069: Manifold Absolute Pressure – Barometric Pressure Correlation


A correlation problem between the MAP sensor and the air mass sensor is indicated by the P0066 DTC code. You are better equipped to address the problem in an efficient manner if you understand its nature, causes, symptoms, diagnosis practices, errors, seriousness, potential repairs, and associated codes. In order to provide a correct diagnosis and resolution of the P0066 DTC Code, it is recommended that you consult with an expert mechanic where you are not sure or require assistance.

P0066 Code – What Does It Mean & How To Fix It