#
MASS AIR FLOW (MAF) SENSOR INSPECTION

BHE014013215W02

  Note

  • Before performing the following inspection, make sure to follow the troubleshooting flowchart. (See Troubleshooting Procedure.)

## Visual Inspection

1. Visually inspect the MAF/IAT sensor for the following:

  • Damage, cracks
  • Rusted sensor terminal
  • Bent sensor terminal

  – If there is any malfunction, replace the MAF/IAT sensor. (See MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION.)
  – If the monitor item condition (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 ON position.

3. As the air gradually approaches the MAF detection part of the MAF/IAT sensor, verify that the voltage at PCM terminal 5N (WDS PID: MAF) varies.

  • If it cannot be verified even though the related harnesses have no malfunction, replace the MAF/IAT sensor. (See MASS AIR FLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR REMOVAL/INSTALLATION.)

  AT

  Engine speed | Engine load calculated value (WDS PID: LOAD) | Intake MAF (WDS PID: MAF)
  --- | --- | ---
  Idle after warm-up (no load) | 20-28% | 4.4-5.3 g/s
  2,500 rpm | 15.0-21.0% | 9.5-12.5 g/s

  MT

  Engine speed | Engine load calculated value (WDS PID: LOAD) | Intake MAF (WDS PID: MAF)
  --- | --- | ---
  Idle after warm-up (no load) | 18.0-25.0% | 3.8-4.7 g/s
  2,500 rpm | 13.5-19.5% | 8.7-11.7 g/s

## Circuit Open/Short Inspection

1. Disconnect the PCM connector.

2. Disconnect the MAF/IAT sensor connector.

3. Inspect the following wiring harnesses for open or short circuit. (Continuity inspection)

### Open circuit

  • If there is no continuity in the following wiring harnesses, there is an open circuit. Repair or replace the wiring harness.
  – MAF/IAT sensor terminal A and main relay terminal C
  – MAF/IAT sensor terminal B and PCM terminal 5U
  – MAF/IAT sensor terminal C and PCM terminal 5N

### Short circuit

  • If there is continuity in the following wiring harnesses, there is a short circuit. Repair or replace the wiring harness.
  – MAF/IAT sensor terminal A and body ground
  – MAF/IAT sensor terminal C and power supply
  – MAF/IAT sensor terminal C and body ground