Toyota prius 3rd gen Mass Air Flow Meter Assembly (D5)

Toyota Prius 3 ^rd Generation (XW30)

Air Flow Meter Assembly Wiring Guide: DIY Pinout Diagram

What is: A Vehicle Mass Air Flow (MAF) Meter Assembly measures the amount of air entering the engine. It sends this data to the Engine Control Module (ECM), which uses it to calculate the correct fuel injection for efficient combustion. Accurate MAF readings help improve engine performance, fuel economy, and emissions control by maintaining the proper air–fuel mixture.

Air Flow Meter Assembly (22204-21010)

OEM Mass Air Flow Meter Assembly for Toyota Prius 2010–2015

Toyota 22204-21010 MAF sensor front and rear views

Toyota Prius 3rd Gen Mass Air Flow Meter Assembly 22204-21010

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1. Introduction

      The  Toyota Prius 3rd Generation Mass Air Flow Meter Assembly (22204-21010) is a critical sensor used to measure the precise amount of air entering the engine intake system. This information is sent to the Engine Control Module (ECM) to accurately control fuel injection timing and quantity, ensuring optimal air-fuel mixture. In the Prius hybrid system, accurate airflow measurement is essential for smooth engine operation, efficient fuel economy, and reduced exhaust emissions. The MAF sensor also plays an important role in engine load calculation, idle stability, and throttle response. A properly functioning MAF meter supports reliable hybrid performance and overall drivability.

Related parts and Accessories

• Engine Control Module (ECM) :-Processes MAF data to control fuel injection, ignition timing, and engine operation.
• Throttle Body Assembly :-Regulates the amount of air entering the engine based on driver demand and ECM control.
• Air Cleaner (Air Filter) Housing:-Filters dust and debris from intake air before it reaches the MAF sensor and engine.
• Fuel Injectors :-Spray precisely metered fuel into the engine cylinders for combustion.
• Oxygen (A/F) Sensors:-Monitor exhaust oxygen levels to fine-tune the air-fuel ratio.
• Manifold Absolute Pressure (MAP) Sensor :-Detects intake manifold pressure to assist in engine load calculation.
• Electronic Throttle Control System:-Electronically manages throttle opening for smooth and efficient engine response.

2. Video Explanation (Quick Overview)

The Mass Air Flow Meter ensures accurate airflow measurement, supporting smooth hybrid operation, improved fuel efficiency, stable engine performance, and reduced emissions in the Toyota Prius 3rd Generation.

3. Air Flow Meter Assembly Wiring Diagram & Pinout

A. Connector Location

• Air Flow Meter Assembly Position: Located in the intake air duct between the air cleaner housing and throttle body.
• Connector Type:
  • D5 (5 pin) Black housing

B. Wiring Table

Mass Air Flow Meter Assembly (D5)

D5 TERMINALS OF Mass Air Flow Meter Assembly CONECTOR

Terminal No	Symbol (Pin Definition)	Wiring (Color Code) & Color	Electrical Paths
D5-1	THA	(P) Pink	➔ D28 116 (THA) [Engine Control Module]
D5-2	E2	(BR) Brown	➔ D28 93 (ETHA) [Engine Control Module]
D5-3	+B	(B) Black	➔ ✠ ➔ DA2 4 ➳ 1 2 ➤ 10A Blade Fuse [EFI NO.2]
D5-4	E2G	(W) White	➔ D28 117 (E2G) [Engine Control Module]
D5-5	VG	(B) Black	➔ D28 94 (VG) [Engine Control Module]

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4. Quick Pin Summary – D5 Connector

5-Pin Black Connector

• D5-1 THA (Intake Air Temperature Signal) :
  Measures the temperature of the intake air using the built-in thermistor inside the MAF sensor. The ECM supplies a reference voltage and monitors the return signal to adjust fuel injection based on air density. Connected to Engine Control Module (ECM), connector D28, terminal 116 (THA).
• D5-2 E2 (Sensor Ground – Intake Air Temperature) :
  Provides the ground reference for the intake air temperature sensor circuit. Ensures accurate THA voltage reading by stabilizing the sensor ground potential. Connected to Engine Control Module (ECM), connector D28, terminal 93 (ETHA).
• D5-3 +B (Power Supply) :
  Supplies battery voltage to power the Mass Air Flow Meter electronics. Power is provided when the EFI system is active, allowing the MAF sensor to operate. Connected to EFI No.2 power circuit through 10A blade fuse.
• D5-4 E2G (Sensor Ground – MAF Circuit) :
  Acts as the main ground reference for the airflow measurement circuit. Stabilizes the VG signal output to ensure accurate airflow calculation by the ECM. Connected to Engine Control Module (ECM), connector D28, terminal 117 (E2G).
• D5-5 VG (Mass Air Flow Signal Output):
  Outputs a voltage signal proportional to the amount of air entering the engine. The ECM uses this signal to calculate engine load, fuel injection quantity, and ignition control. Connected to Engine Control Module (ECM), connector D28, terminal 94 (VG).

Quick Note: The D5 Mass Air Flow Meter connector supplies power, ground, and signal paths that allow the ECM to calculate engine load accurately. The +B circuit powers the sensor, while E2 and E2G provide stable ground references. The VG signal represents actual airflow entering the engine, and THA reports intake air temperature. Using these inputs, the ECM adjusts fuel injection, ignition timing, idle control, and emissions, ensuring smooth hybrid engine operation and optimal fuel efficiency in the Toyota Prius 3rd Gen (XW30).