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.
Diagnosis Procedure
- CHECK INTAKE SYSTEM
Check the following for connection.
- Air duct
- Vacuum hoses
- Intake air passage between air duct and intake manifold
Is the inspection result normal?
YES: GO TO 2.
NO: Reconnect the parts.
- CHECK MASS AIR FLOW (MAF) SENSOR POWER SUPPLY
- Turn ignition switch OFF.
- Disconnect MAF sensor harness connector.
- Turn ignition switch ON.
- Check the voltage between MAF sensor harness connector and ground.
+ - Voltage MAF sensor Connector Terminal F4 5 Ground Battery voltage Is the inspection result normal?
YES: GO TO 4.
NO: GO TO 3.
- CHECK MASS AIR FLOW (MAF) SENSOR POWER SUPPLY CIRCUIT
- Turn ignition switch OFF.
- Disconnect IPDM E/R harness connector.
- Check the continuity between MAF sensor harness connector and IPDM E/R harness connector.
+ - Continuity MAF sensor IPDM E/R Connector Terminal Connector Terminal F4 5 E14 35 Existed - Also check harness for short to ground.
Is the inspection result normal?
YES: Perform the trouble diagnosis for power supply circuit.
NO: Repair or replace error-detected parts.
- CHECK MAF SENSOR GROUND CIRCUIT
- Turn ignition switch OFF.
- Disconnect ECM harness connector.
- Check the continuity between MAF sensor harness connector and ECM harness connector.
+ - Continuity MAF sensor ECM Connector Terminal Connector Terminal F4 4 F25 9 Existed - Also check harness for short to power.
Is the inspection result normal?
YES: GO TO 5.
NO: Repair or replace error-detected parts.
- CHECK MAF SENSOR INPUT SIGNAL CIRCUIT
- Check the continuity between MAF sensor harness connector and ECM harness connector.
+ - Continuity MAF sensor ECM Connector Terminal Connector Terminal F4 3 F25 13 Existed - Also check harness for short to ground and to power.
Is the inspection result normal?
YES: GO TO 6.
NO: Repair or replace error-detected parts
- Check the continuity between MAF sensor harness connector and ECM harness connector.
- CHECK INTAKE AIR TEMPERATURE SENSOR 1
Check the intake air temperature sensor 1. Refer to "COMPONENT INSPECTION ".
Is the inspection result normal?
YES: GO TO 7.
NO: Replace MAF sensor (with intake air temperature sensor 1). Refer to "EXPLODED VIEW ".
- CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
Check the EVAP control system pressure sensor. Refer to "COMPONENT INSPECTION ".
Is the inspection result normal?
YES: GO TO 8.
NO: Replace EVAP control system pressure sensor. Refer to "2WD: EXPLODED VIEW ".
- CHECK MAF SENSOR
Check the MAF sensor. Refer to "COMPONENT INSPECTION ".
Is the inspection result normal?
YES: Check intermittent incident. Refer to "INTERMITTENT INCIDENT ".
NO: Replace MAF sensor. Refer to "EXPLODED VIEW ".
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.