2019 Infiniti M35 V6-3.5L (VQ35HR) Diagnostic and Repair Information Page 340
P0139, P0159 HO2S2
Description
The heated oxygen sensor 2, after three way catalyst 1, monitors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the air fuel ratio (A/F) sensor 1 are shifted, the air-fuel ratio is controlled to stoichiometric, by the signal from
the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates voltage from approximately 1 V in richer conditions to 0 V in leaner conditions.
Under normal conditions the heated oxygen sensor 2 is not used for engine control operation.
DTC Logic
DTC DETECTION LOGIC
The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/F) sensor 1. The oxygen storage
capacity of the three way catalyst 1 causes the longer switching time. To judge the malfunctions of heated oxygen sensor
2, ECM monitors whether the switching response of the sensor's voltage is faster than specified during various driving conditions such as fuel cut.
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure 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.
Will CONSULT-III be used?
YES - GO TO 2.
NO - GO TO 4.
2.PERFORM DTC CONFIRMATION PROCEDURE
With CONSULT-III
TESTING CONDITION:
For better results, perform "DTC WORK SUPPORT" at a temperature of 0 to 30 锟紺 (32 to 86 锟紽).
1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
6. Let engine idle for 1 minute.
7. Select "DATA MONITOR" mode with CONSULT-III.
