DTC P0138, P0158 HO2S2
EC-245
C
D
E
F
G
H
I
J
K
L
M
A
EC
DTC P0138, P0158 HO2S2
PFP:226A0
Component Description
ABS002HC
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas on each bank.
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
ABS002HD
Specification data are reference values.
On Board Diagnosis Logic
ABS002HE
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 before the three way catalyst (manifold) causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the voltage is unusually high during
the various driving condition such as fuel-cut.
SEF327R
MONITOR ITEM
CONDITION
SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)
●
Warm-up condition
●
After keeping the engine speed
between 3,500 and 4,000 rpm for 1
minute and at idle for 1 minute
under no load
Revving engine from idle up to
3,000 rpm quickly.
0 - 0.3V
←→
Approx. 0.6 - 1.0V
HO2S2 MNTR (B1)
HO2S2 MNTR (B2)
●
Warm-up condition
●
After keeping the engine speed
between 3,500 and 4,000 rpm for 1
minute and at idle for 1 minute
under no load
Revving engine from idle up to
3,000 rpm quickly.
LEAN
←→
RICH
PBIB1877E
DTC No.
Trouble diagnosis name
DTC detecting condition
Possible cause
P0138
0138
(Bank 1)
Heated oxygen sensor 2
circuit high voltage
An excessively high voltage from the sensor
is sent to ECM.
●
Harness or connectors
(The sensor circuit is open or shorted)
●
Heated oxygen sensor 2
P0158
0158
(Bank 2)