EC-262
[QG (WITH EURO-OBD)]
DTC P0139 HO2S2 (M/T MODELS)
DTC P0139 HO2S2 (M/T MODELS)
PFP:226A0
Component Description
EBS00QL5
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas.
Even if switching characteristics of the heated oxygen 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 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.
CONSULT-II Reference Value in Data Monitor Mode
EBS00QL6
Specification data are reference values.
On Board Diagnosis Logic
EBS00QL7
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the heated oxygen sensor 1. The oxygen
storage capacity of the three way catalyst (manifold) causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the switching response of the sen-
sor's voltage is faster than specified during the various driving condi-
tion such as fuel-cut.
SEF327R
MONITOR ITEM
CONDITION
SPECIFICATION
HO2S2 (B1)
●
Engine: After warming up
●
Keeping the engine speed
between 3,500 and 4,000 rpm
for one minute and at idle for
one minute under no load
Revving engine from idle to 3,000
rpm quickly.
0 - 0.3V
←→
Approx. 0.6 - 1.0V
HO2S2 MNTR (B1)
LEAN
←→
RICH
SEF302U
DTC No.
Trouble diagnosis name
DTC detecting condition
Possible cause
P0139
0139
Heated oxygen sensor 2
circuit slow response
It takes more time for the sensor to respond
between rich and lean than the specified time.
●
Harness or connectors
(The sensor circuit is open or shorted.)
●
Heated oxygen sensor 2
●
Fuel pressure
●
Injectors
●
Intake air leaks