DTC P0136 Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2) DTC P0156 Oxygen Sensor Circuit Malfunction (Bank 2 Sensor 2)
DTC P0136 Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2) DTC P0156 Oxygen Sensor Circuit Malfunction (Bank 2 Sensor 2)
DTC P0136 Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2) DTC P0156 Oxygen Sensor Circuit Malfunction (Bank 2 Sensor 2)
CIRCUIT DESCRIPTION
Refer to DTC P0130 on page 05−102.
DTC No. DTC Detection Condition Trouble Area
The following condition (a) or (b) continues for 500 seconds or
S Open or short in heated oxygen sensor circuit
more:
P0136 S Heated oxygen sensor (Bank 1, 2 Sensor 2)
(a) During driving with the engine warmed up, heated oxygen
P0156 S Heated oxygen sensor heater (Bank 1, 2 Sensor 2)
sensor output does not change
S EFI relay
(b) Heated oxygen sensor output is very low most of the time
HINT:
S Bank 1 refers to the bank that includes cylinder No.1.
S Bank 2 refers to the bank that does not include cylinder No.1.
S Sensor 2 refers to the sensor farthest away from the engine body.
MONITOR DESCRIPTION
The heated oxygen sensor generates waveform of the voltage between 0 V and 1 V in response to the oxy-
gen concentration in the exhaust gases . When the output voltage of the heated oxygen sensor is 0.55 V
or more, the ECM judges that the air−fuel ratio is RICH. When it is 0.40 V or less, the ECM judges that the
air−fuel ratio is LEAN.
If the rear heated oxygen sensor output does not change between RICH and LEAN during ”Stop and GO”
driving, the ECM interprets this as malfunction in the sensor and sets a DTC. Also, if the sensor output re-
mains at less than 0.05 V for more than 126 seconds (when ECM monitored the sensor for 210 seconds while
the air−fuel feedback is being performed), the ECM will interpret this as a fault. In either case, the ECM will
turn on the MIL and set a DTC.
MONITOR STRATEGY
P0136: Heated oxygen sensor (Bank 1 Sensor 2) output voltage (Crack)
P0136: Heated oxygen sensor (Bank 1 Sensor 2) output voltage
Related DTCs
P0156: Heated oxygen sensor (Bank 2 Sensor 2) output voltage (Crack)
P0156: Heated oxygen sensor (Bank 2 Sensor 2) output voltage
WIRING DIAGRAM
Refer to DTC P0130 on page 05−102.
CONFIRMATION DRIVING PATTERN
(f)
Once Twice
12 times
Vehicle speed 40 seconds 40 seconds
40 seconds
or more or more
or more
25 mph
(40 km/h) (d) (d) (d)
A58686
INSPECTION PROCEDURE
HINT:
Hand−held tester only:
It is possible the malfunctioning area can be found using the ACTIVE TEST A/F CONTROL operation. The
A/F CONTROL operation can determine if the A/F sensor, heated oxygen sensor or other potential trouble
areas are malfunctioning or not.
(a) Perform the ACTIVE TEST A/F CONTROL operation.
HINT:
The A/F CONTROL operation lowers the injection volume 12.5% or increases the injection volume 25%.
(1) Connect the hand−held tester to the DLC3 on the vehicle.
(2) Turn the ignition switch to ON.
(3) Warm up the engine by running the engine at 2,500 rpm for approximately 90 seconds.
(4) Select the item: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
(5) Perform the A/F CONTROL operation with the engine in an idle condition (press the right or left
button).
Result:
Heated oxygen sensor reacts in accordance with increase and decrease of injection volume:
+25 % → rich output: More than 0.5 V
−12.5 % → lean output: Less than 0.4 V
NOTICE:
There is a delay of few seconds in the sensor 1 (front sensor) output, and there is about 20 seconds
delay at maximum in the sensor 2 (rear sensor).
Output voltage of heated oxygen Output voltage of heated oxygen Main suspect
sensor (sensor 1: front sensor) sensor (sensor 2: rear sensor) trouble area
Injection volume Injection volume
+25 % +25 %
−12.5 % −12.5 %
⎯
Case 1 Output voltage Output voltage
More than 0.5 V More than 0.5 V
Less than 0.4V
OK Less than 0.4V
OK
The following A/F CONTROL procedure enables the technician to check and graph the voltage outputs of
both the heated oxygen sensor.
To display the graph, enter ACTIVE TEST/ A/F CONTROL/USER DATA, then select ”O2S B1S1 and O2S
B1S2” or ”O2S B2S1 and O2S B2S2” by pressing the ”YES” button followed by the ”ENTER” button and then
the ”F4” button.
NOTICE:
If the vehicle is short of fuel, the air−fuel ratio becomes LEAN and heated oxygen sensor DTCs will
be recorded, and the MIL then illuminates.
HINT:
S If different DTCs related to different systems that have terminal E2 as the ground terminal are output
simultaneously, terminal E2 may be open.
S Read freeze frame data using the hand−held tester or the OBD II scan tool. Freeze frame data records
the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can
help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air−fuel
ratio was lean or rich, and other data from the time the malfunction occurred.
S A high heated oxygen sensor (sensor 1) voltage (0.55 V or more) could be caused by a rich air fuel
mixture. Check for conditions that would cause the engine to run rich.
S A low heated oxygen sensor (sensor 1) voltage (0.4 V or less) could be caused by a lean air fuel mix-
ture. Check for conditions that would cause the engine to run lean.
1 CHECK OTHER DTC OUTPUT(IN ADDITION TO DTC P0136 AND/OR P0156)
(a) Connect the hand−held tester or the OBD II scan tool to the DLC3.
(b) Turn the ignition switch to ON and turn the hand−held tester or the OBD II scan tool ON.
(c) Select the item: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
(d) Read the DTCs.
Result:
Display (DTC output) Proceed to
P0136 and/or P0156 A
P0136 or P0156 and other DTCs B
HINT:
If any other codes besides P0136 and/or P0156 are output, perform troubleshooting for those DTCs first.
B GO TO RELEVANT DTC CHART
(See page 05−47)
(a) Connect the hand−held tester or the OBD II scan tool to the DLC3.
(b) Start the engine and turn the hand−held tester or the OBD II scan tool ON.
(c) Select the item: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
(d) After warming up the engine, run the engine at 2,500 rpm for 3 minutes.
(e) Read the output voltage of the heated oxygen sensor when the engine speed is suddenly increased.
HINT:
Quickly accelerate the engine to 4,000 rpm 3 times by using the accelerator pedal.
Heated oxygen sensor output voltage: Alternates from 0.4 V or less to 0.5 V or more.
OK Go to step 6
NG
OK
(a) Remove the EFI relay from the engine room R/B.
(b) Check for continuity in the EFI relay.
Standard:
Tester Connection Specified Condition
1−2 Continuity
3−5 No continuity
Continuity
3−5
(Apply battery voltage to terminals 1 and 2)
B16200
(c) Reinstall the EFI relay.
NG REPLACE EFI RELAY
OK
Wire Harness Side: (a) Disconnect the H6 or H8 heated oxygen sensor connec-
Heated Oxygen Sensor Connector tor.
H6 (b) Disconnect the E6 ECM connector.
HT
B1S2 (c) Check the resistance between the wire harness side con-
nectors.
H8
Standard (Check for open):
B2S2
Tester Connection Specified Condition
OX
OX (H6−3) − OX1B (E6−29)
Front View
A79118 HT (H6−1) − HT1B (E6−5)
Below 1 Ω
OX (H8−3) − OX2B (E6−21)
HT (H8−1) − HT2B (E6−25)
Standard (Check for short):
E6 Tester Connection Specified Condition
OX (H6−3) or OX1B (E6−29) − Body ground
HT (H6−1) or HT1B (E6−5) − Body ground
10 kΩ or higher
OX (H8−3) or OX2B (E6−21) − Body ground
HT1B OX2B HT (H8−1) or HT2B (E6−25) − Body ground
HT2B (d) Reconnect the heated oxygen sensor connector.
OX1B
ECM Connector A55007
A55005 (e) Reconnect the ECM connector.
MREL
A72920
OK
HINT:
Clear all DTCs prior to performing the confirmation driving pattern.
GO
7 READ OUTPUT DTC(SEE IF DTC P0136 AND/OR P0156 ARE OUTPUT AGAIN)
(a) Connect the hand−held tester or the OBD II scan tool to the DLC3.
(b) Turn the ignition switch to ON and turn the hand−held tester or the OBD II scan tool ON.
(c) Select the item: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
(d) Read the DTCs.
Result:
Display (DTC output) Proceed to
No output A
P0136 and/or P0156 B