The DTC codeP0108 OBD2 refers to a problem in the MAP sensor circuit (Multiple Absolute Pressure Sensor) and indicates that there is a voltage input that is too high for the PCM (Power Train Control Module).
The MAP (Manifold Absolute Pressure) sensor delivers information on the voltage reading as it changes to the PCM (Powertrain Control Module) through a signal cable.
When the engine vacuum increases, the voltage reading is low. When the vehicle is idling, the voltage should be at 1 volt and about 5 volts when the vehicle is accelerated. In case the PCM notices that the MAP sensor voltage reading is not within the expected range, diagnostic code P0108 is established.
When accelerating the vehicle you can present instability.
Low fuel economy.
Black smoke comes out of the exhaust.
Causes of OBD2 P0108 Generic
The reasons why the fault code P0108 OBD II can be established are:
There may be leaks in the vacuum supply line to the Multiple Absolute Pressure Sensor (MAP).
Maybe there is a vacuum leak from the engine.
The signal cable from the Manifold Absolute Pressure (MAP) sensor to the Powertrain Control Module (PCM) may be short-circuited.
The MAP sensor ground circuit may be shorted.
MAP sensor may be defective.
Possible solutions of the DTC code P0108 Generic
Before the code P0108 you can do the following to solve it:
For a good diagnosis, the first thing you could do is with the switch on and using a scanning tool, compares the reading of the Multiple Absolute Pressure Sensor (MAP) with the barometric pressure. Both readings must be equal, since both measure the atmospheric pressure. If the MAP sensor reading is greater than 0.5 volts from the BARO reading you must replace the MAP sensor.
If not, you can check the reading of the Manifold Absolute Pressure (MAP) sensor at idle, which should be around 1.5 volts. If that is the case, the problem indicates that it is intermittent, that is why you can manipulate the cable system and the connector to see if the problem returns. Also, check the vacuum hoses, as they may be damaged. Change some of these components and if necessary, you can replace them.
If the MAP sensor reading exceeds 4.5 volts, check the actual reading of the motor vacuum, with the motor running. If this is less than 15 or 16 Hg, it means that the Power Train Control Module (PCM) is not observing enough vacuum, so that the operation is optimal, and thus causing a signal of higher voltage of the expected Therefore, repair that defect in the vacuum of the engine.
If the actual reading of the motor vacuum is greater than 16 Hgs, disconnect the MAP sensor and measure with your scan tool, which should result in no voltage present. Check that the ground of the Powertrain Control Module (PCM) is intact, just as the terminals and the connector of the Multiple Absolute Pressure Sensor are well adjusted. If all is well, you must replace the MAP sensor.
But if a voltage reading is obtained with the sensor disconnected, it is a signal of a short circuit in the MAP sensor cable system, find it and proceed to perform the respective repairs.