What does it mean?
OBD II code P0106 is defined as “ Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem”, and is set when the PCM (Power Train Control Module) detects a signal voltage from the MAP (Manifold Absolute Pressure) sensor that is abnormal with regard to the current engine load or throttle position, or a signal voltage that does not show a valid relationship with the MAP sensor.
Changes in the signal voltage is interpreted by the PCM as variations, or fluctuations in the intake manifold pressure when compared with ambient atmospheric pressure. In most applications, the PCM will detect and store code P0106 when an incorrect signal voltage is present for more than four continuous seconds, with reference to a signal voltage that applies to each particular application.
In terms of operating principles, the PCM uses data from the MAP sensor related to the pressure, or vacuum in the intake manifold to monitor the engine load in order to calculate an appropriate fuel delivery strategy for the current engine load, as well as the proper air/fuel ratio for that load. Note however that some applications use a BARO (Barometric) sensor that is incorporated into the MAF (Mass Airflow Sensor) instead of a dedicated MAP sensor.
In these cases, the BARO sensor senses changes in ambient air pressure as a vehicle’s altitude above sea level changes. Still other applications make use of a combined MAF/BARO sensor with a redundant, but integrated MAP sensor as a backup should the MAF sensor fail. In yet another variation, the ECM (Engine Control Module) in some cars use data from the MAP sensor to monitor the EGR (Exhaust Gas Recirculation) system, in addition to checking the validity of data from other sensors.
From this is should be obvious that other codes could accompany P0106; if other codes are indeed present, these codes should be investigated first, since P0106 could be set as the result of malfunctions and failures in systems that are not directly related to the MAP sensor. While there are some design differences between MAP sensors made by different manufacturers, all MAP sensors are located on the inlet manifold.
The image below shows the typical location of MAP sensors on four cylinder engines. Note: A Range/Performance related code will be set when either a sensor or other component does not perform within the range the PCM (Powertrain Control Module) expects to see, given the current engine load/speed, and information gathered from other sensors.
The possible causes of Range/Performance codes are likely to be defective sensors as easily as they are likely to be the result of wiring issues that affect the operation of the affected sensor or component, which means that with these codes, it is important to regard all sensors and components as part of the control circuit the code refers to.