What is a MAP Sensor? (Manifold Absolute Pressure)
The MAP sensor stands for Manifold Absolute Pressure sensor. It measures the air pressure inside the intake manifold and sends this data to the ECU (Engine Control Unit) to calculate the correct fuel injection amount.
Function of the MAP Sensor
- Measures intake manifold air pressure.
- Determines engine load.
- Helps ECU adjust fuel-air mixture.
- Improves fuel economy and reduces emissions.
- Assists in ignition timing control.
Location of the MAP Sensor
- Mounted directly on the intake manifold.
- Connected via a vacuum hose in some vehicles.
- Sometimes located near the throttle body.
Symptoms of a Faulty MAP Sensor
- Poor engine performance.
- Increased fuel consumption.
- Engine hesitation or unstable RPM.
- Hard starting condition.
- Black smoke from exhaust.
- Check Engine Light ON.
Related OBD-II Trouble Codes
- P0105 – MAP sensor circuit malfunction
- P0106 – MAP sensor range/performance issue
- P0107 – MAP sensor low input
- P0108 – MAP sensor high input
- P0109 – MAP sensor intermittent signal
MAP Sensor Electrical Circuit
A MAP sensor usually has 3 wires:
- 5V Reference from ECU
- Ground
- Signal wire to ECU
The sensor converts air pressure into a variable voltage signal sent to the ECU.
Voltage Range
- Power supply: about 5 volts constant
- Signal output:
- 0.5V – 1.5V at idle (high vacuum)
- 3V – 4.5V at full throttle (high load)
Types of MAP Sensors
- Analog MAP sensor
- Digital MAP sensor
- Combined MAP + IAT sensor
- Turbo MAP sensor (high pressure range)
Repair / Replacement Cost
- Cleaning: very low cost or free
- Wiring diagnostics: depends on workshop
- Replacement: approximately $25 – $150 depending on vehicle
Important Notes
A bad MAP sensor is not always the cause of engine problems. Similar symptoms may come from a faulty MAF sensor, vacuum leaks, or a dirty throttle body. Proper OBD diagnosis is recommended before replacement.