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.
2007 Mazda Mazdaspeed3 L4-2.3L TurboFACTORY OEM SERVICE PROCEDURE
Air Flow Meter/Sensor: Testing and Inspection
MASS AIR FLOW (MAF) SENSOR INSPECTION[L3 WITH TC]
Visual Inspection
NOTE: Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See HOW TO USE THIS MANUAL.)
1. Visually inspect for the following on the MAF sensor. - Damage
- Cracks
- Bent terminals
- Terminal rust
- If any of the above are found, replace the MAF/IAT sensor.
- If the monitor item status/specification (reference) is not within the specification even though there is no malfunction, perform the "Circuit Open/Short Inspection".
Voltage Inspection
1. Remove the MAF/IAT sensor without disconnect the MAF/IAT sensor connector.
2. Turn the ignition switch to the ON position.
3. As the air gradually approaches the MAF detection part of the MAF/IAT sensor, verify that the voltage at PCM terminal 1AK (M-MDS PID: MAF) varies.
- If it cannot be verified even though the related harnesses have no malfunction, replace the MAF/IAT sensor.
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Disconnect the MAF/IAT sensor connector.
3. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)
Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- MAF/IAT sensor terminal A and main relay terminal A
- MAF/IAT sensor terminal B and PCM terminal 1P
- MAF/IAT sensor terminal C and PCM terminal 1AK
Short circuit
- If there is continuity, there is a short circuit. Repair or replace the wiring harness.
- MAF/IAT sensor terminal A and body ground
- MAF/IAT sensor terminal B and power supply
- MAF/IAT sensor terminal C and power supply
- MAF/IAT sensor terminal C and body ground
Visual Inspection
NOTE: Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. (See HOW TO USE THIS MANUAL.)
1. Visually inspect for the following on the MAF sensor. - Damage
- Cracks
- Bent terminals
- Terminal rust
- If any of the above are found, replace the MAF/IAT sensor.
- If the monitor item status/specification (reference) is not within the specification even though there is no malfunction, perform the "Circuit Open/Short Inspection".
Voltage Inspection
1. Remove the MAF/IAT sensor without disconnect the MAF/IAT sensor connector.
2. Turn the ignition switch to the ON position.
3. As the air gradually approaches the MAF detection part of the MAF/IAT sensor, verify that the voltage at PCM terminal 1AK (M-MDS PID: MAF) varies.
- If it cannot be verified even though the related harnesses have no malfunction, replace the MAF/IAT sensor.
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Disconnect the MAF/IAT sensor connector.
3. Inspect the following wiring harnesses for an open or short circuit. (Continuity check)
Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- MAF/IAT sensor terminal A and main relay terminal A
- MAF/IAT sensor terminal B and PCM terminal 1P
- MAF/IAT sensor terminal C and PCM terminal 1AK
Short circuit
- If there is continuity, there is a short circuit. Repair or replace the wiring harness.
- MAF/IAT sensor terminal A and body ground
- MAF/IAT sensor terminal B and power supply
- MAF/IAT sensor terminal C and power supply
- MAF/IAT sensor terminal C and body ground
Factory Service Tools
Use the Manual With the Right Hardware
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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.
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