Air Flow Meter/Sensor: Testing and Inspection
MASS AIRFLOW (MAF)/INTAKE AIR TEMPERATURE (IAT) SENSOR INSPECTION [AJ]NOTE: Perform the following test only when directed.
MAF Sensor Voltage Inspection
1. Turn the ignition switch to LOCK.
2. Disconnect the PCM connector.
3. Connect the SST (104 Pin Breakout Box) to the PCM connector and the PCM as shown.
4. Tighten the connector attaching bolt.
Tightening torque: 3.0 - 5.4 N.m {30 - 56 kgf.cm, 27 - 48 in.lbf}
5. Turn the ignition switch to ON.
6. Measure the voltage between the breakout box pins 10 and 11.
- If not as specified, perform the "MAF Sensor Circuit Open/Short Inspection".
Specification: 0.0 - 0.1 V
7. Turn the ignition switch to START and warm up the engine completely.
8. Measure the voltage between the breakout box pins 10 and 11.
- If not as specified, perform the "MAF Sensor Circuit Open/Short Inspection".
Specification: 0.5 - 0.8 V
MAF Sensor Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Connect the SST (104 Pin Breakout Box) with the PCM disconnected.
3. Tighten the connector attaching bolt.
Tightening torque: 3.0 - 5.4 N.m {30 - 56 kgf.cm, 27 - 48 in.lbf}
4. Inspect the following wiring harness for open or short circuit (Continuity check).
Open circuit
- If there is no continuity, the circuit is open. Repair or replace the harness.
- MAF/IAT sensor terminal B (harness-side) and main relay terminal C (harness-side)
- MAF/IAT sensor terminal E (harness-side) and 104 pin breakout box terminal 11
- MAF/IAT sensor terminal D (harness-side) and 104 pin breakout box terminal 10
Short circuit
- If there is continuity, the circuit is shorted. Repair or replace the harness.
- MAF/IAT sensor terminal B (harness-side) and body ground
- MAF/IAT sensor terminal E (harness-side) and power supply
- MAF/IAT sensor terminal E (harness-side) and body ground
- MAF/IAT sensor terminal D (harness-side) and power supply
MAF Rate and Load Value
NOTE: The scan tool shows the MAF rate and load value.
IAT Sensor Resistance Inspection
1. Disconnect the MAF/IAT sensor connector.
2. Measure the resistance between MAF/IAT sensor terminals A and F using an ohmmeter.
- If not as specified, replace the MAF/IAT sensor.
- If the IAT sensor is okay, but the IAT PID is out of specification, perform the "IAT Sensor Circuit Open/Short Inspection".
IAT Sensor Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Connect the SST (104 Pin Breakout Box) without connecting to the PCM as shown.
3. Tighten the connector attaching bolt.
Tightening torque: 3.0 - 5.4 N.m {30 - 56 kgf.cm, 27 - 48 in.lbf}
4. Inspect the following wiring harness for open or short circuit (Continuity check).
Open circuit
- If there is no continuity, the circuit is open. Repair or replace the harness.
- MAF/IAT sensor terminal A (harness-side) and 104 pin breakout box terminal 20
- MAF/IAT sensor terminal F (harness-side) and 104 pin breakout box terminal 15
Short circuit
- If there is continuity, the circuit is shorted. Repair or replace the harness.
- MAF/IAT sensor terminal A (harness-side) and power supply
- MAF/IAT sensor terminal F (harness-side) and power supply
- MAF/IAT sensor terminal F (harness-side) and body ground