P0108 Chrysler 3.5L – Test a 300M MAP Sensor

The P0108 Chrysler OBDII trouble code relates to the Manifold Absolute Pressure sensor that is mounted to the intake manifold assembly of your 3.5 liter engine in your Chrysler 300M. Typically this check engine code means that your sensor is the sensor or the wiring from the sensor to your ECU is experiencing an issue. The specific language of this OBDII trouble code is MAP Pressure Circuit High Input, and today I will be showing you how to test a 300M MAP sensor to see what is causing your trouble code.

Operating as a simple pressure sensor, the MAP is responsible for giving your Chrysler PCM real time data about how much air is entering your engine. When this sensor begins to fail or in this case sends a signal that’s higher than what the PCM is normally expecting, your P0108 Chrysler OBDII trouble code is triggered.

The 300M MAP sensor happens to be a four pin unit, meaning that the Intake Air Temperature (IAT or AIT) sensor is incorporated into the unit. This makes the function and testing of your pressure sensor that much more important, because without the proper signal serious damage could occur. Your Chrysler 300M PCM cannot calculate proper air/fuel ratios or orchestrate the ignition spark timing without this signal making sense.


If you think your 300M MAP sensor is failing, you may experience some drivability issues before the P0108 trouble code is triggered. Some of these 300M driving problems could include but is not limited to;

  • Harsh Shifting
  • Hard Starting
  • Rough Idle

Use this guide to test your 300M manifold sensor easily by removing the MAP connector and probing the sensor for internal resistance as well as making sure the PCM is providing the sensor with power and ground.

Common causes of the P0108 Check Engine Light

  • Failing MAP Sensor
  • Blocked or leaking MAP sensor oring
  • Break in MAP sensor wires

Where is the 300M MAP sensor located?

This sensor is mounted to the intake assembly and can be found easily by opening your Chrysler 300M engine bay. The sensor is mounted to the driver side of the intake manifold and can be located by looking at the right side of the engine bay.


What is the 300M MAP Sensor part number?

The part number for this sensor can vary depending on availability. Some of these interchange part numbers are 18060 or PS10023 and there are several cutover part numbers to other vendors such as 779-11591, 1903-302626, and 213-1338.


Because the nature of this test relates to the signal being sent from the MAP sensor, we are using a multimeter to read the values real time from the sensor itself during the testing period. If you own a OBDII scan tool that’s capable of providing real time values from the PCM, plug in now to check the MAP or pressure sensor values to fix your P0108 Chrysler code.

How To Test a 300M MAP Sensor


To fix your Chrysler 300M P0108 OBDII trouble code, the wire you will need to pay is labeled as PIN A above in the 300M MAP sensor wiring diagram. We are going to be testing the wire with your key inserted into the ignition and turned to the “ON” position. Using the multimeter, read the PIN A for voltage with the engine off but the key turned to the “ON” position.

You should have 4.5 volts at this wire with the key turned to the “ON” position. If the voltage is not correct, replace your MAP sensor immediately and clear your OBDII trouble code with the scan tool.

If you do have this voltage, the next step is to test your MAP sensor using an air compressor. Monitor your MAP sensor signal while gently opening your air intake box and blowing air into your air intake. Open your throttle body manually to ensure that airflow reaches your intake manifold. Make sure to use low pressure settings here and gently blow into the air box assembly.

Monitor your MAP sensor signal here and you should see your MAP signal of 4.5 increasing as air pressure increases. If your sensor is not rising in voltage to match the lack of vacuum, replace your sensor and use a scan tool to clear your code. Congratulations you now know how to test a 300M MAP Sensor. Have any questions about this guide? Leave me a message below and let me know!

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