EC-214
< COMPONENT DIAGNOSIS >
[VQ35HR]
P0139, P0159 HO2S2
P0139, P0159 HO2S2
Description
INFOID:0000000003133375
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 sig-
nal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.
DTC Logic
INFOID:0000000003133376
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 oxy-
gen 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 the various driving condition
such as fuel-cut.
DTC CONFIRMATION PROCEDURE
1.
INSPECTION START
Do you have CONSULT-III?
Do you have CONSULT-III?
YES
>> GO TO 2.
NO
>> GO TO 5.
2.
PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
For better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30
°
C (32 to 86
°
F).
>> GO TO 3.
3.
PERFORM DTC CONFIRMATION PROCEDURE
With CONSULT-III
SEF327R
SEF302U
DTC No.
Trouble diagnosis name
DTC detecting condition
Possible cause
P0139
Heated oxygen sensor 2
(bank 1) circuit slow re-
sponse
It takes more time for the sensor to respond be-
tween rich and lean than the specified time.
• Harness or connectors
(The sensor circuit is open or shorted)
• Heated oxygen sensor 2
• Fuel pressure
• Fuel injector
• Intake air leaks
P0159
Heated oxygen sensor 2
(bank 2) circuit slow re-
sponse