Understanding the wiring of your Toyota’s 5-wire mass air flow (MAF) sensor is crucial for proper engine performance and diagnostics. This article provides a comprehensive guide to the Toyota 5 wire MAF sensor wiring diagram, covering different models and potential issues.
The MAF sensor measures the amount of air entering the engine, allowing the engine control unit (ECU) to calculate the correct fuel injection. A faulty MAF sensor can lead to poor fuel economy, rough idling, and even engine stalling. This sensor incorporates a hot wire to measure airflow and a thermistor to measure intake air temperature, both critical for accurate fuel delivery.
A typical Toyota 5-wire MAF Sensor
Identifying Your Toyota 5 Wire MAF Sensor Wiring
There are two common wiring configurations for the Toyota 5-wire MAF sensor. Differentiating between them is essential before any troubleshooting or replacement. The easiest way to identify the correct configuration is by measuring the resistance across the thermistor (THA) terminals using an ohmmeter.
- Early Wiring Configuration: Resistance of approximately 2.21kΩ to 2.69kΩ at 20°C (68°F) between pins 1 and 2.
- Later Wiring Configuration: Resistance of approximately 2.21kΩ to 2.69kΩ at 20°C (68°F) between pins 4 and 5.
THA Resistance Curve for a Toyota MAF Sensor
Toyota 5 Wire MAF Sensor Wiring Diagrams
Below are the wiring diagrams for both configurations, detailing each pin’s function:
Early Configuration (e.g., JZS161 2JZGE before 07/2000, JZS161 2JZGTE, JZA80 2JZGTE VVTi)
| Pin | Symbol | Definition | Input/Output | Description |
|---|---|---|---|---|
| 1 | THA | Air Temperature Sensor | Output | Sends air temperature data to the ECU. |
| 2 | E2 | Sensor Ground (Air Temperature Sensor) | Input | Ground for the air temperature sensor. |
| 3 | EVG | Mass Airflow Sensor Ground | Input | Ground for the MAF sensor signal. |
| 4 | +B | EFI Main Relay Switched Power | Input | Power supply to the MAF sensor. |
| 5 | VG | Engine Airflow | Output | Sends airflow data to the ECU. |
Later Configuration (e.g., JZS161 2JZGE after 07/2000, JZS171 1JZGTE)
| Pin | Symbol | Definition | Input/Output | Description |
|---|---|---|---|---|
| 1 | +B | EFI Main Relay Switched Power | Input | Power supply to the MAF sensor. |
| 2 | EVG (or E2G) | Mass Airflow Sensor Ground | Input | Ground for the MAF sensor signal. |
| 3 | VG | Engine Airflow | Output | Sends airflow data to the ECU. |
| 4 | THA | Air Temperature Sensor | Output | Sends air temperature data to the ECU. |
| 5 | E2 | Sensor Ground (Air Temperature Sensor) | Input | Ground for the air temperature sensor. |
Another example of a Toyota 5-wire MAF Sensor
Troubleshooting a Toyota 5 Wire MAF Sensor
If you suspect a faulty MAF sensor, refer to a factory repair manual for specific diagnostic procedures for your Toyota model. Common symptoms of a failing MAF sensor include:
- Poor fuel economy
- Rough idling
- Hesitation or stumbling during acceleration
- Engine stalling
- Check Engine Light illumination
Conclusion
This guide provides a detailed overview of the Toyota 5 Wire Mass Air Flow Sensor Wiring Diagram. Correctly identifying your specific wiring configuration is paramount for accurate diagnostics and repair. Always consult your vehicle’s repair manual for detailed troubleshooting procedures and safety precautions. Understanding your MAF sensor’s wiring is a key step towards maintaining optimal engine performance and fuel efficiency.
