P0136
DTC P0136 Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)CIRCUIT DESCRIPTION
DTC Detection Condition:
The Heated Oxygen (HO2) sensor is used to monitor the oxygen concentration in the exhaust gas. For optimum operation of the Three-Way Catalytic Converter (TWC), the air-fuel mixture must be maintained near the stoichiometric ratio. The HO2 sensor output voltage changes suddenly in the vicinity of the stoichiometric ratio. The ECM adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric level. The HO2 sensor generates a voltage between 0.1 V and 0.9 V in response to the oxygen concentration in the exhaust gas.
If the oxygen concentration in the exhaust gas increases, the air-fuel ratio is LEAN. The HO2 sensor voltage drops below 0.45 V and informs the ECM of the LEAN condition. If oxygen is not in the exhaust gas, the air-fuel ratio is RICH. The HO2 sensor voltage increases above 0.45 V and informs the ECM of the RICH condition.
HINT: Sensor 2 refers to the sensor farthest away from the engine assembly.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
Component Operating Range:
O2S Test Result (Mode 05 Data):
The ECM monitors the HO2 sensor (sensor 2) as follows:
- The HO2 sensor voltage does not remain Rich (above 0.5 Volts) or Lean (below 0.4 volts) while the vehicle is accelerated and decelerated for 4 to 8 minutes. If the voltage remains either Rich or Lean, the ECM interprets this as a malfunction, illuminates the MIL and sets a DTC.
- The HO2 sensor voltage does not remain at less than 0.05 V for a long time while the vehicle is running. If the voltage remains at less than 0.05 V for a long time, the ECM interprets this as a malfunction, illuminates the MIL and sets a DTC.
- The sensor voltage drops below 0.2 V (extremely Lean condition) immediately when the vehicle decelerates and fuel-cut operates. If the voltage does not drop below 0.2 V, the ECM determines that the response feature of the sensor has deteriorated, illuminates the MIL and sets a DTC.
Wiring Diagram:
CONFIRMATION DRIVING PATTERN
CAUTION: Strictly observe posted speed limits, traffic laws, and road conditions when conducting the drive pattern.
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to ON.
c. Turn the tester ON.
d. Clear DTCs.
e. Allow the engine to idle for 2 minutes.
f. Warm up the engine until the engine coolant temperature (ECT) reaches 75 °C (167 °F).
g. Allow the vehicle to run at 48 km/h (30 mph) or more for 40 seconds or more.
h. Stop the vehicle and allow the engine to idle for 20 seconds or more.
i. Repeat the steps (g) and (h) at least 8 times in one driving cycle.
j. Move the shift lever into the second gear.
k. Depress the accelerator pedal at least 10 seconds.
l. Allow the vehicle to run at 48 km/h (30 mph) or more.
m. Immediately after step (I), release the accelerator pedal for at least 10 seconds without depressing the brake pedal (to execute fuel-cut).
n. Decelerate the vehicle until the vehicle speed drops less than 10 km/h (6 mph).
o. Repeat the step (k), (l), (m) and (n) at least twice in one driving cycle.
HINT:
The HO2 sensor monitor operates when the following conditions are met:
- 2 minutes or more passed after the engine start.
- The ECT is 75 °C (167 °F) or more.
- Cumulative running time at 48 km/h (30 mph) or more exceeds 6 minutes.
- Closed loop.
- Fuel-cut is operated for 8 seconds or more.
INSPECTION PROCEDURE
HINT:
Hand-held tester only:
Malfunctioning areas can be found by performing the ACTIVE TEST / A/F CONTROL operation (Heated Oxygen [HO2] sensor or other trouble areas). The A/F CONTROL operation can determine whether the front HO2 sensor (sensor 1), rear HO2 sensor (sensor 2) and other potential trouble areas are malfunctioning or not.
a. Perform A/F CONTROL using the hand-held tester.
HINT: The A/F Control operation lowers the fuel injection volume by 12.5 % or increases the injection volume by 25 %.
1. Connect the hand-held tester to the DLC3.
2. Turn the ignition switch to ON and turn the hand-held tester ON.
3. Warm up the engine by running the engine at 2,500 rpm for approximately 90 seconds.
4. On the hand-held tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
5. Perform the A/F CONTROL operation with the engine in an idling condition (press the right or left button).
Result:
Rear heated oxygen sensor reacts in accordance with increase and decrease of the fuel injection volume.
+25 % -> Rich output: More than 0.5 V -12.5 % -> Lean output: Less than 0.4 V
NOTE: The front heated oxygen sensor has an output delay of a few seconds and the rear heated oxygen sensor has a maximum output delay of approximately 20 seconds.
Following A/F CONTROL procedure enables the technician to check and graph the voltage outputs of both front and rear heated oxygen sensors.
To display the graph, enter ACTIVE TEST/A/F CONTROL / USER DATA, select "O2S B1S1 and O2S B1S2" by pressing the "YES" button followed by the "ENTER" button and then the "F4" button.
NOTE: If the vehicle is short of fuel, the air-fuel ratio becomes LEAN and heated oxygen sensor DTCs are set, and the MIL then comes on.
Step 1 - 2:
Step 3 - 4:
Step 5:
Step 6 - 7:
HINT:
- If different DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
- Read freeze frame data using the hand-held tester. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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.
- If the 0X1 B wire from the ECM connector is short-circuited to the +B wire, DTC P0136 is set.
CHECK FOR INTERMITTENT PROBLEMS
HINT:
Hand-held tester only:
Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect with the hand-held tester when the ECM is in check mode. In check mode, the ECM uses 1trip detection logic, which is more sensitive to malfunctions than normal mode (default) that uses 2trip detection logic.
a. Clear DTCs.
b. Switch the ECM from normal mode to check mode using a hand-held tester.
c. Perform a simulation test.
d. Check and wiggle the harness(es), the connector(s) and terminal(s).