Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Manifold Absolute Pressure Sensor Description
The Manifold Absolute Pressure (MAP) sensor measures the changes in the intake manifold pressure which result from engine load and speed changes. It converts these to a voltage output.
A closed throttle on engine coast down produces a relatively low MAP output. MAP is the opposite of vacuum. When manifold pressure is high, vacuum is low. The MAP sensor is also used to measure barometric pressure. This is performed as part of MAP sensor calculations. With the ignition ON and the engine not running, the engine control module (ECM) will read the manifold pressure as barometric pressure and adjust the air/fuel ratio accordingly. This compensation for altitude allows the system to maintain driving performance while holding emissions low. The barometric function will update periodically during steady driving or under a wide open throttle condition. In the case of a fault in the barometric portion of the MAP sensor, the ECM will set to the default value.
A failure in the MAP sensor circuit sets a diagnostic trouble code P0107 or P0108.
The following tables show the difference between absolute pressure and vacuum related to MAP sensor output, which appears as the top row of both tables.
MAP
| Volts | 4.9 | 4.4 | 3.8 | 3.3 | 2.7 | 2.2 |
| kPa | 100 | 90 | 80 | 70 | 60 | 50 |
| in. Hg | 29.6 | 26.6 | 23.7 | 20.7 | 17.7 | 14.8 |
| Volts | 1.7 | 1.1 | 0.6 | 0.3 | 0.3 |
| kPa | 40 | 30 | 20 | 10 | 0 |
| in. Hg | 11.8 | 8.9 | 5.9 | 2.9 | 0 |
VACUUM
| Volts | 4.9 | 4.4 | 3.8 | 3.3 | 2.7 | 2.2 |
| kPa | 0 | 10 | 20 | 30 | 40 | 50 |
| in.Hg | 0 | 2.9 | 5.9 | 8.9 | 11.8 | 14.8 |
| Volts | 1.7 | 1.1 | 0.6 | 0.3 | 0.3 |
| kPa | 60 | 70 | 80 | 90 | 100 |
| in.Hg | 17.7 | 20.7 | 23.7 | 26.7 | 29.6 |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.