Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSSUBARU2012IMPREZA WRX STI F4-2.5L DOHC TURBOREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSAIR TEMPERATURE SENSOR ( AMBIENT / INTAKE )TESTING AND INSPECTION
2012 Subaru Impreza WRX STI F4-2.5L DOHC Turbo
Air Temperature Sensor ( Ambient / Intake ): Testing and Inspection
2012 Subaru Impreza WRX STI F4-2.5L DOHC TurboSECTION Testing and Inspection
Mass Air Flow and Intake Air Temperature Sensor
INSPECTION
CHECK THE MASS AIR FLOW SENSOR UNIT
1. Connect the battery positive terminal to terminal No. 3 and the battery ground terminal to terminal No. 4, the circuit tester positive terminal to terminal No. 5 and the circuit tester ground terminal to terminal No. 4.
2. Check the voltage changes when air is blown to the mass air flow sensor unit in arrow direction.
CHECK THE INTAKE AIR TEMPERATURE SENSOR UNIT
Measure the resistance between intake air temperature sensor terminals.
OTHER INSPECTIONS
1. Check that the mass air flow and intake air temperature sensor has no deformation, cracks or other damages.
2. Check that the mass air flow and intake air temperature sensor has no dirt.
INSPECTION
CHECK THE MASS AIR FLOW SENSOR UNIT
1. Connect the battery positive terminal to terminal No. 3 and the battery ground terminal to terminal No. 4, the circuit tester positive terminal to terminal No. 5 and the circuit tester ground terminal to terminal No. 4.
2. Check the voltage changes when air is blown to the mass air flow sensor unit in arrow direction.
CHECK THE INTAKE AIR TEMPERATURE SENSOR UNIT
Measure the resistance between intake air temperature sensor terminals.
OTHER INSPECTIONS
1. Check that the mass air flow and intake air temperature sensor has no deformation, cracks or other damages.
2. Check that the mass air flow and intake air temperature sensor has no dirt.
RENDER: 1.0x
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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.