What does it mean?
OBD II fault code P0107 is defined as “ Manifold Air Pressure/Barometric Pressure Circuit Low Input”, and is set when the PCM (Powertrain Control Module) detects a signal from the MAP (Manifold Air Pressure Sensor) that falls outside of the expected value for the reigning engine load or throttle position, or otherwise fails to correlate with the actual pressure/vacuum in the intake manifold.
All applications use data from the manifold pressure (or vacuum) to calculate an appropriate fuel delivery strategy to suit the current engine load, and to make suitable adjustments to ignition timing as well as valve/cam timing on applications where VVT or VCS systems are present. From this it should be obvious that incorrect or invalid data can cause serious disruptions in the smooth and efficient operation of an engine.
On most applications, a fault code is set when the PCM detects a mismatch between the throttle position and the signal voltage from the MAP sensor for more than four continuous seconds. The deviation from the correct sensor voltage is measured against a reference voltage for the particular application.
However, the four-second code setting parameter may differ between applications, which makes it important to consult the manual for the vehicle being worked on for accurate information on code setting parameters. Note: Circuit Low Input codes are often the result of low battery voltages (that can have many possible causes), bad connections across electrical connectors or previously repaired wiring, as well as corrosion in electrical connectors.
Other possible causes of low input voltages include poor installation of aftermarket components, poor quality aftermarket components like fuses, relays, and switches, and modification of the electrical system that could include the use of conductors that are not rated for use in a particular application. However, poor connections often result in high resistances in some parts of the circuit, which is why it is important to perform resistance and continuity checks during the diagnostic procedure.