A MAP sensor or manifold absolute pressure sensor is a device that measures the pressure inside the intake manifold of an internal combustion engine. The pressure measurement is used to calculate the amount of air flow into the engine. This information is used by the engine control unit (ECU) to adjust the fuel injector timing and air/fuel mixture.
Map sensors are typically located on the side of the intake manifold near the throttle body. The manifold absolute pressure sensor works by the changes induced by the intake air pressure applied on the silicon chip. The MAP sensor comes in different wiring diagrams and colors depending on the car. In this powerful guide, we will discuss the 3 and 4-pin MAP sensor wiring diagram.
MAP Sensor Wiring Diagram
The Manifold Absolute Pressure Sensor or MAP Sensor wiring diagram can be different according to the year, make, and model.
In this powerful guide, we will be more general than specific. Here, I will give you a general idea of how the MAP sensor wiring is designed. For your specific make and model, check the car owner’s manual. The color of wires will vary and are color-coded depending upon the brand of the sensor.
3 Pin MAP Sensor Wiring Diagram
A three-wire MAP sensor has three wires, power, ground, and signal, which are listed below.
- Hot Power Wire (5 Volt Reference Voltage comes from the ECU)
- Ground Wire
- Signal Wire (Gives Signals to the ECU)
The hot wire is a feed power source that is connected to the car computer (ECU). This is a reference voltage, which means the car ECU Powers the MAP sensor on this wire.
The ground wire is also taken from the ECU. This ground wire gives earth to the MAP sensor. A third wire is a signal wire means the MAP sensor delivers the data (signal) to the car ECU through this wire.
4 Pin MAP Sensor Wiring Diagram
A four-wire manifold absolute pressure sensor has the following four wires.
- 12 Volt Feed Positive Power Wire
- Ground Wire
- MAP Signal Wire
- Intake Air Temperature (IAT) Sensor Signal Wire
A 4-wire manifold absolute pressure sensor has a 5-volt reference voltage, which is connected to the car computer (ECU). A reference voltage means the ECU provides the voltage to the sensor.
The ground wire also goes to the car ECU. The MAP Signal Wire goes to the car ECU. The signal wire means the MAP sensor sends the Output Voltage to the ECU.
A four-wire MAP sensor has an additional sensor called the intake air temperature sensor. It has only an IAT signal wire, which sends the temperature of the air inside the intake manifold to the car computer.