Airflow Meter

WARNING: On Prius, read service precautions before proceeding with service procedure. See SERVICE PRECAUTIONS .

NOTE: Airflow meter may also be referred to as Mass Airflow (MAF) meter.

Remove airflow meter. See AIRFLOW METER under ENGINE SENSORS & SWITCHES in REMOVAL & INSTALLATION - 4-CYLINDER article.

Using ohmmeter, check resistance between terminals E2 and THA on airflow meter. See Fig 1-Fig 4 . Resistance should be within specification in relation to temperature. See AIRFLOW METER RESISTANCE table. Replace airflow meter if resistance is not within specification.

AIRFLOW METER RESISTANCE

Application & Temperature

Ohms

Camry

-4°F (-20°C)

13,600-18,400

68°F (20°C)

2210-2690

140°F (60°C)

493-667

Camry Solara, Celica & Corolla

-4°F (-20°C)

13,600-18,400

68°F (20°C)

2210-2690

140°F (60°C)

490-670

ECHO

⁽¹⁾

Highlander

-4°F (-20°C)

13,600-18,400

68°F (20°C)

2210-2690

140°F (60°C)

493-667

MR2, Matrix, Prius & RAV4

-4°F (-20°C)

13,600-18,400

68°F (20°C)

2210-2690

140°F (60°C)

490-670

Tacoma

-4°F (-20°C)

10,000-20,000

32°F (0°C)

4000-7000

68°F (20°C)

2000-3000

104°F (40°C)

900-1300

140°F (60°C)

400-700

176°F (80°C)

200-400

⁽¹⁾	For Air Flow Meter testing, see appropriate SELF-DIAGNOSTICS article.

Airflow meter operation should be checked. On Camry and Highlander, go to next step. On Camry Solara, Celica, Corolla, ECHO, MR2, Prius, RAV4 and Tacoma, go to step 5.
Apply battery voltage to +B terminal on airflow meter and battery ground to E2G terminal on airflow meter. See Fig 1 . Connect voltmeter leads to proper terminals on airflow meter. See Fig 1. Apply air into designated area on airflow meter and note voltage reading. See Fig 1. While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate.
Install electrical connector on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. See Fig 5-Fig 7 . Turn ignition on. Apply air into designated area on airflow meter and note voltage reading. See Fig 1 and Fig 5-Fig 7 . While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Turn ignition off. Remove voltmeter.

Fig 1: Identifying Airflow Meter Terminals, Air Application Area & Voltmeter Connections (Camry & Highlander)

Fig 2: Testing Airflow Meter Resistance (Camry Solara, Celica, ECHO, MR2, Prius & RAV4)

Fig 3: Testing Airflow Meter Resistance (Corolla)

Fig 4: Testing Airflow Meter Resistance (Tacoma)

Fig 5: Testing Airflow Meter Operation (Camry Solara, Celica, ECHO, MR2, Prius & RAV4)

Fig 6: Testing Airflow Meter Operation (Corolla)

Fig 7: Testing Airflow Meter Operation (Tacoma)