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 measures changes in manifold pressure. Changes in manifold pressure result from engine load and speed changes. The MAP sensor converts these changes in manifold pressure into a voltage output signal to PCM (1.5 volts at idle to about 4.5 volts at WOT). The PCM can monitor these signals and adjust air/fuel ratio and ignition timing under various operating conditions.
If MAP sensor fails, the PCM substitutes a fixed MAP value, and uses the TP sensor to control fuel delivery. A fault in the MAP circuit should set a related trouble code. If a related trouble code is not present and MAP sensor is suspected of causing a driveability problem, perform functional check of MAP sensor. See SYSTEM/COMPONENT TESTS - GASOLINE article in the ENGINE PERFORMANCE section.
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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.