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Questions and Answers

Saturn SL2 MAP/BARO Sensors

Q. Hi Vincent, On a 1998 Saturn SL2, is the BARO sensor and the MAP sensor the same thing or are they two different sensors???

Thanks for your help in advance.

Saturn SL2 MAP/BARO Sensors

A. The Manifold Absolute Pressure (MAP) sensor is mounted on the intake manifold. The MAP sensor measures the intake manifold pressure. Engine vacuum is related to engine load and RPM changes. A high vacuum signal indicates a low intake manifold pressure. A low vacuum signal indicates a high intake manifold pressure. The higher the pressure signal, the greater the load being placed on the engine.

The MAP sensor voltage is scaled by the PCM to pressure (kPa or psi). A high pressure (atmospheric pressure) produces an output of 4.5 to 5.0 volts, about 95 to 105 kPa (14 to 15 psi). A low pressure (engine vacuum) produces about 0.5 to 0.90 volts, about 37 to 50 kPa (5 to 7psi). The MAP sensor is also used to calculate barometric pressure under certain conditions.

By monitoring the MAP sensor output voltage signal, the PCM determines the manifold pressure and can increase or decrease the injector On-time (or pulse width). The PCM also uses the MAP sensor signal to help control fuel, ignition timing, canister purge duty cycle and EGR operation.

Additional Information provided courtesy of AllDATA

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