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.
2012 Infiniti QX56 AWDFACTORY OEM SERVICE PROCEDURE
Component Inspection (MAP sensor)
- CHECK MAP SENSOR-I
- Turn ignition switch OFF.
- Start engine and warm it up to normal operating temperature.
- Turn ignition switch OFF, wait at least 5 seconds and then turn ON.
- Check the voltage between ECM harness connector terminals as follows.
ECM + - Connector Terminal Connector Terminal F110 67 F110 70 NOTE:- To avoid the influence of intake manifold vacuum, check the voltage 1 or more minutes past after engine is stopped.
- Because the sensor is absolute pressure sensor, output value may differ depending on atmospheric pressure and altitude.
- Measure the atmospheric pressure.NOTE: As the atmospheric pressure described on the synoptic chart is the value at sea level, compensate the pressure with the following chart.
Altitude (m) Compensated pressure (hPa) 0 0 200 -24 400 -47 600 -70 800 -92 1000 -114 1500 -168 2000 -218 - Check the manifold absolute pressure sensor value corresponding to the atmospheric pressure.
Atmospheric pressure (hPa) Voltage (V) 800 3.1 - 3.7 850 3.3 - 3.9 900 3.5 - 4.1 950 3.8 - 4.3 1000 4.0 - 4.6 1050 4.2 - 4.8 Courtesy of NISSAN NORTH AMERICA, INC.
Is the inspection result normal?
YES: GO TO 2.
NO: Replace MAP sensor.
- CHECK MAP SENSOR-II
- Start engine and let it idle.
- Check intake manifold vacuum.
- Check the voltage between ECM harness connector terminals as per the following.
ECM + - Connector Terminal Connector Terminal F110 67 F110 70 - Confirm the difference of the voltage when engine is stopped and at idling is within the values shown in the following chart.
Intake manifold vacuum [kPA (mmHg)] Voltage difference (V) -40 (-300) 1.5 - 2.0 -53.3 (-400) 2.0 - 2.6 -66.7 (-500) 2.6 - 3.2 -80 (-600) 3.2 - 3.8 Is the inspection result normal?
YES: INSPECTION END
NO: Replace MAP sensor.
Factory Service Tools
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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.