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AIRFLOW METER Toyota 4Runner III

Engine Controls - System & Component Testing - V6 & V8 8 illustrations ~691 words

AIRFLOW METER

Note. Airflow meter may be referred to as Mass Airflow (MAF) meter.

Scheme 249

Scheme 249: Avalon, Camry, Camry Solara & Sienna
Scheme 249: Avalon, Camry, Camry Solara & Sienna

Scheme 250

Scheme 250
Scheme 250
  1. Turn ignition off. Disconnect electrical connector at airflow meter. Airflow meter is bolted to side of air intake hose, near upper cap on air cleaner assembly. Remove airflow meter with gasket and note airflow meter terminal identification. (Scheme 249)
  2. Using ohmmeter, check resistance between terminals E2 and THA. Resistance should be within specification in relation to the temperature. See «AIRFLOW METER RESISTANCE»(ref-91239-S29791888242001030600000) table. Replace airflow meter if resistance is not within specification.
  3. To test airflow meter operation, ensure electrical connector is installed on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 250)
  4. Turn ignition on. Apply air into airflow meter and note voltage reading. (Scheme 250) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Remove voltmeter. Reinstall airflow meter using NEW gasket.

Scheme 251

Scheme 251: Land Cruiser
Scheme 251: Land Cruiser

Scheme 252

Scheme 252
Scheme 252
  1. Turn ignition off. Disconnect electrical connector at airflow meter. Airflow meter is bolted to top side of air intake hose, near upper cap on air cleaner assembly. Remove airflow meter and note airflow meter terminal identification. (Scheme 251)
  2. Using ohmmeter, check resistance between terminals E2 and THA. Resistance should be within specification in relation to the temperature. See «AIRFLOW METER RESISTANCE»(ref-91239-S29791888242001030600000) table. Replace airflow meter if resistance is not within specification.
  3. To test airflow meter operation, ensure electrical connector is installed on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 252)
  4. Turn ignition on. Apply air into airflow meter and note voltage reading. (Scheme 252) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Remove voltmeter. Reinstall airflow meter.

Scheme 253

Scheme 253: Tacoma & 4Runner
Scheme 253: Tacoma & 4Runner

Scheme 254

Scheme 254
Scheme 254
  1. Turn ignition off. Disconnect electrical connector at airflow meter. Airflow meter is bolted to air intake hose, near air cleaner assembly. Remove airflow meter with "O" ring (if equipped) and note airflow meter terminal identification. (Scheme 253)
  2. Using ohmmeter, check resistance between terminals E2 and THA. Resistance should be within specification in relation to the temperature. See «AIRFLOW METER RESISTANCE»(ref-91239-S29791888242001030600000) table. Replace airflow meter if resistance is not within specification.
  3. To test airflow meter operation, ensure electrical connector is installed on airflow meter. Connect voltmeter leads to proper terminals on airflow meter with electrical connector installed. (Scheme 254)
  4. Turn ignition on. Apply air into airflow meter and note voltage reading. (Scheme 254) While air is being applied, voltage reading should fluctuate. Replace airflow meter if voltage does not fluctuate. Remove voltmeter. Reinstall airflow meter using "O" ring (if equipped).
TemperatureOhms
Avalon, Camry, Camry Solara & Sienna
4°F (-20°C)14,600-17,800
68°F (20°C)2210-2690
140°F (60°C)290-350
Land Cruiser
4°F (-20°C)12,500-16,900
68°F (20°C)2190-2670
140°F (60°C)500-680
Tacoma & 4Runner
4°F (-20°C)13,600-18,400
68°F (20°C)2200-2700
140°F (60°C)500-700

AIRFLOW METER RESISTANCE

Scheme 255

Scheme 255: Avalon, Camry Solara & Land Cruiser
Scheme 255: Avalon, Camry Solara & Land Cruiser
  1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of brake pedal. Note terminal identification on the brakelight switch. (Scheme 255)
  2. Using ohmmeter, check that continuity exists between terminals No. 1 and 2 with brake pedal depressed. Check that no continuity exists between terminals No. 1 and 2 with brake pedal released.
  3. Check that no continuity exists between terminals No. 3 and 4 with brake pedal depressed. Check that continuity exists between terminals No. 3 and 4 with brake pedal released. Adjust or replace brakelight switch if operation is not as described.

Scheme 256

Scheme 256: Camry, Sienna, Tacoma & 4Runner
Scheme 256: Camry, Sienna, Tacoma & 4Runner
  1. Disconnect electrical connector at brakelight switch. Brakelight switch is located near top of the brake pedal. Note terminal identification on brakelight switch. (Scheme 256)
  2. On models without cruise control, use ohmmeter to check that no continuity exists between terminals No. 1 and 2 with brake pedal released. Check that continuity exists between terminals No. 1 and 2 with brake pedal depressed. Adjust or replace brakelight switch if operation is not as described.
  3. On models with cruise control, use ohmmeter to check that no continuity exists between terminals No. 1 and 2 with brake pedal released. Check that continuity exists between terminals No. 1 and 2 with brake pedal depressed.
  4. Check that no continuity exists between terminals No. 3 and 4 with brake pedal depressed. Check that continuity exists between terminals No. 3 and 4 brake pedal released. Adjust or replace brakelight switch if operation is not as described.