Nissan Murano: Dtc/circuit Diagnosis / P0127 Iat Sensor

DTC Description

DTC DETECTION LOGIC

Rationally incorrect voltage from the sensor is sent to ECM, compared with the voltage signal from engine coolant temperature sensor.

POSSIBLE CAUSE

• Harness and connectors (The sensor circuit is open or shorted)

• Intake air temperature sensor

FAIL-SAFE

Not applicable

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next test.

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Turn ignition switch ON.

3. Turn ignition switch OFF and wait at least 10 seconds.

TESTING CONDITION:

This test may be conducted with the drive wheels lifted in the shop or by driving the Nissan Murano vehicle. If a road test is expected to be easier, it is unnecessary to lift the vehicle.

GO TO 2.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT

1. Wait until engine coolant temperature is less than 96°C (205°F)

   1. Turn ignition switch ON.

   2. Select “DATA MONITOR” mode with CONSULT.

   3. Check the engine coolant temperature.

   4. If the engine coolant temperature is not less than 96°C (205°F), turn ignition switch OFF and cool down engine.

      NOTE:

      Perform the following steps before engine coolant temperature is above 96°C (205°F).

2. Turn ignition switch ON.

3. Select “DATA MONITOR” mode with CONSULT.

4. Start engine.

5. Hold Nissan Murano vehicle speed at more than 70 km/h (43 MPH) for 100 consecutive seconds.

   CAUTION:

   Always drive Nissan Murano vehicle at a safe speed.

6. Check 1st trip DTC.

With GST

Follow the procedure “With CONSULT” above.

Is 1st trip DTC detected?

Proceed to Diagnosis Procedure.

To check malfunction symptom before repair: Refer to Intermittent Incident.

Confirmation after repair: INSPECTION END

CHECK INTAKE AIR TEMPERATURE SENSOR

Check intake air temperature sensor. Refer to Component Inspection.

Is the inspection result normal?

INSPECTION END

Replace mass air flow sensor (with intake air temperature sensor).

CHECK INTAKE AIR TEMPERATURE SENSOR

1. Turn ignition switch OFF.

2. Disconnect mass air flow sensor harness connector.

3. Check resistance between mass air flow sensor terminals as per the following.

   Mass air flow sensor		Condition		Resistance (kΩ)
   +	−
   Terminals
   4	2	Temperature [°C (°F)]	25 (77)	1.800 - 2.200

Is the inspection result normal?

INSPECTION END

Replace mass air flow sensor. Refer to Removal and Installation.