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How to Replace a Neon MAP Sensor

by David McGuffin

The MAP (manifold absolute pressure) sensor is placed on the front portion of the Neon's air intake manifold and has two small screws securing it into place. MAP sensors are responsible for identifying the air pressure within the manifold and sending a reading to the engine's ECU (engine control unit) relating the voltage level for the spark in the ignition cylinder. If your MAP sensor is faulty, you will notice a reduction of power, backfiring and hesitation when accelerating. It is important to first test related engine components before replacing the MAP sensor.

Plug an OBD II scanner into your Neon's OBD port, which is typically located to underneath your steering column near the driver's door. The OBD port will always be within a 2 to 3 feet of the steering column on any car manufactured since 1995. Turn on the scanner and turn the Neon's ignition key to the accessories position. If your scanner does not translate the troubleshoot code, then you will need to look it up on a website such as OBD Codes or an online repair manual found at AutoZone (see Resources).

Inspect your air intake assembly and vacuum lines leading from the intake to the manifold for leaks and disconnected joints. Turn the engine on and feel around the vacuum hoses attached to the manifold for any spurting of pressurized air. Use gaffer's tape to plug up and secure any leaks or disjointed lines that are leaking. Also check the air filter for extreme dirtiness and replace it if necessary. If you do any repairs to the intake, you will need to clear out the OBD code using your scanner and drive your Neon for at least 25 miles in order to make sure that your MAP sensor will not trigger the check engine light again.

Check the MAP sensor's electrical connection by using a multimeter or voltmeter. Disconnect the electrical connection leading to your MAP sensor. The electrical connection should read between 4.5 volts and 5.0 volts when the engine is turned on and the probes are touching the terminals on the electrical connection. If the terminals do not read the correct voltage, or if they are completely dead, then you may have an electrical problem rather than a failed MAP sensor.

Replace the MAP sensor by unscrewing it from the air intake assembly. Disconnect the electrical connection. Screw in the new MAP sensor with a screwdriver or socket wrench. Reconnect the electrical connection. Clear out the MAP sensor troubleshoot code using the OBD scanner.

Tip

  • Other possible components that could trigger the MAP sensor to temporarily malfunction include the EGR (exhaust gas regulation) valve or an issue with the PCV valve (positive crankcase ventilation).

Items you will need

About the Author

David McGuffin is a writer from Asheville, N.C. and began writing professionally in 2009. He has Bachelor of Arts degrees from the University of North Carolina, Asheville and Montreat College in history and music, and a Bachelor of Science in outdoor education. McGuffin is recognized as an Undergraduate Research Scholar for publishing original research on postmodern music theory and analysis.

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