Mass Air Flow Sensor

WARNING: This page is about a different car, the 2012 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.

With CONSULT

Reconnect all harness connectors disconnected.
Start engine and warm it up to normal operating temperature.
Connect CONSULT and select "DATA MONITOR" mode.

Select "MAS A/F SE-B1" and check indication under the following conditions.

Condition

MAS A/F SE-B1 (V)

Ignition switch ON (Engine stopped.)

Approx. 0.4

Idle (Engine is warmed-up to normal operating temperature.)

1.0 - 1.3

2, 500 RPM (Engine is warmed-up to normal operating temperature.)

1.7 - 2.1

Idle to approximately 4, 000 RPM

1.0 - 1.3 to Approx. 2.4⁽¹⁾

⁽¹⁾	Check for linear voltage rise in response to engine being increased to approximately 4, 000 RPM.

If the voltage is out of specification, proceed the following.
1. Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
  - Crushed air ducts
  - Malfunctioning seal of air cleaner element
  - Uneven dirt of air cleaner element
  - Improper specification of intake air system parts
2. If NG, repair or replace malfunctioning part and perform steps 2 to 4 again.
If OK, go to next step.
Turn ignition switch OFF.
Disconnect mass air flow sensor harness connector and reconnect it again.
Perform steps 2 to 4 again.
If NG, clean or replace mass air flow sensor. Refer to AIR CLEANER AND AIR DUCT .

Without CONSULT

Reconnect all harness connectors disconnected.
Start engine and warm it up to normal operating temperature.

Check voltage between ECM terminal 51 (Mass air flow sensor signal) and ground.