Mass Airflow Sensor -G70-, CHECKING: Notes

2012 Volkswagen Jetta TDI, 4D Sedan, Standard TransSECTION Notes

Observe all safety precautions: SAFETY PRECAUTIONS 

View clean working conditions: CLEAN WORKING CONDITIONS 

NOTE:

Use only gold-plated terminals when servicing terminals in harness connector of Mass Air Flow (MAF) Sensor -G70-.

Special tools and workshop equipment required 

  • Multimeter.
  • Wiring diagram.

Test requirements 

  • The fuse is OK.
  • Battery voltage at least 12.5 volts.
  • All electrical consumers such as, lights and rear window defroster, switched off.
  • Vehicles with automatic transmission, shift selector lever into position "P" or "N".
  • A/C switched off.
  • Ground connections between engine/transmission/chassis OK.
  • Coolant Temperature at least 55° C.
  • Ignition switched off.

Test procedure 

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK .

Start diagnosis 

-- Connect the scan tool.

-- Start engine and let idle.

-- Using the scan tool, Check the air flow quantity of the Mass Air Flow (MAF) Sensor -G70- at idle:

Diagnostic text Specified value
Air flow quantity at Mass Air Flow (MAF) sensor  
  • Engine running at idle
2.00 to 5.00 g/sec

-- Switch the ignition OFF.

If the specified value was obtained: 

-- Condition may be intermittent

-- Check the intake duct for air leaks, loose connections.

-- Check the wiring for an open, high resistance or short to ground.

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

-- Go to Final procedures

If the specified value was Not obtained: 

-- Disconnect the Mass Air Flow (MAF) Sensor -G70- electrical harness connector.

-- Switch the ignition On.

-- Using a Multimeter, Check the Mass Air Flow (MAF) Sensor -G70- electrical harness connector terminal 5 to Ground (GND) for voltage.

Specified value: Battery Voltage

-- Switch the ignition OFF.

-- Continue test according to the following table: 

Value Cause Test
If the specified value was not obtained: Open or shorted circuit Checking wiring 
If the specified value was obtained: Check reference signal circuit Checking wiring 
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.