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.

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HOMESERVICE MANUALSINFINITI2019Q70 3.7 LUXE, AWDREPAIR AND DIAGNOSISENGINE PERFORMANCETESTING & DIAGNOSISENGINE CONTROL SYSTEM (3.7L) (DTC/CIRCUIT DIAGNOSIS) (8 OF 9)DTC/CIRCUIT DIAGNOSISDTC P2270: O2 SENSORCOMPONENT FUNCTION CHECK

2019 Infiniti Q70 3.7 Luxe, AWD

Component Function Check

2019 Infiniti Q70 3.7 Luxe, AWDSECTION Component Function Check

PERFORM COMPONENT FUNCTION CHECK-I

Without CONSULT

Start engine and warm it up to the normal operating temperature.
Turn ignition switch OFF and wait at least 10 seconds.
Start engine and keep the engine speed between 3, 500 and 4, 000 RPM for at least 1 minute under no load.
Let engine idle for 1 minute.

Check the voltage between ECM harness connector terminals under the following condition.

DTC	ECM			Condition	Voltage
	Connector	+	-
		Terminal	Terminal
P2270	F128	41	35	Revving up to 4, 000 RPM under no load at least 10 times	The voltage should be below 0.18 V at least once during this procedure.

Is the inspection result normal?

YES

INSPECTION END

GO TO 2.

PERFORM COMPONENT FUNCTION CHECK-II

Check the voltage between ECM harness connector terminals under the following condition.

DTC	ECM			Condition	Voltage
	Connector	+	-
		Terminal	Terminal
P2270	F128	41	35	Keeping engine at idle for 10 minutes	The voltage should be below 0.18 V at least once during this procedure.

Is the inspection result normal?

YES

INSPECTION END

GO TO 3.

PERFORM COMPONENT FUNCTION CHECK-III

Check the voltage between ECM harness connector terminals under the following condition.

DTC	ECM			Condition	Voltage
	Connector	+	-
		Terminal	Terminal
P2270	F128	41	35	Coasting from 80 km/h (50 MPH) in D position	The voltage should be below 0.18 V at least once during this procedure.

Is the inspection result normal?

YES

INSPECTION END

Go to Diagnosis Procedure .

RENDER: 1.0x

NO RELATED

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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.