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 (MAP) Sensor
MAP sensor is mounted on engine compartment firewall. The MAP sensor is used by PCM to calibrate amount of air/fuel mixture supplied to the engine. This sensor measures manifold absolute pressure. Ambient barometric pressure is also measured when ignition switch is first turned on, during engine cranking, and at wide open throttle.
The MAP sensor transmits a low voltage signal (1.5-2.1 volts) at idle when manifold vacuum is high, and a higher voltage signal (3.9-4.8 volts) during open throttle when manifold vacuum is low.
Input voltage (from the PCM) to MAP sensor ranges from 4.8-5.1 volts. Adjustments made as a result of this input will usually affect injector pulse width, ignition timing, idle speed and upshift indicator light.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.