Troubleshooting

DTC P0136 OXYGEN SENSOR CIRCUIT MALFUNCTION (BANK 1 SENSOR 2)

CIRCUIT DESCRIPTION

DTC Detection Condition:

The heated oxygen sensor's output voltage changes sharply when the air-fuel ratio is near the ideal stoichio-metric air-fuel ratio. This sensor reaction is useful for detecting the oxygen concentration in the exhaust gas and for providing the ECM with data about what adjustments are necessary for the air-fuel ratio.

If the oxygen concentration in the exhaust gas increases and the heated oxygen sensor voltage is below 0.45 V, the air-fuel ratio is "LEAN". The heated oxygen sensor informs the ECM about the LEAN condition. If the oxygen concentration in the exhaust gas increases and the heated oxygen sensor voltage is about 0.45 V, the air-fuel ratio is "RICH". The heated oxygen sensor informs the ECM about the RICH condition.

HINT:
- Bank 1 refers to the bank that includes the cylinder No. 1
- Sensor 2 refers to the sensor further away from the engine body.

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

Component Operating Range:

O2S Test Result:

The heated oxygen sensor generates waveform of a voltage between 0 V and 1 V in response to the oxygen concentration in the exhaust gas. When the output voltage of the heated oxygen sensor is 0.5 V or more, the ECM judges that the air-fuel ratio is RICH. When it is 0.4 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 a malfunction in the rear heated oxygen sensor and sets a DTC. Also, when the ECM monitors the heated oxygen sensor for 290 seconds (while air-fuel feedback is being performed) and the rear heated oxygen sensor's output remains at 0.05 V or more for 130 seconds, the ECM will determine this as a fault.

HINT:
*: "Stop" indicates a vehicle speed of 0 km/h (0 mph). "Go" indicates a vehicle speed of 30 km/h (18.6 mph).

Wiring Diagram:

CONFIRMATION DRIVING PATTERN

Confirmation Driving Pattern:

a. Connect the hand-held tester to the DLC3.
b. Switch the hand-held tester from "normal mode" to "check mode".
c. Start the engine and let the engine idle for 60 seconds or more.
d. Drive the vehicle at 40 km/h (25 mph) or more for 40 seconds or more.
e. Let the engine idle for 10 seconds or more.
f. Preform steps (d) to (e) 11 times.

HINT:
- While performing the steps (d) to (e) 11 times, drive the vehicle at over 65 km/h (40 mph) and force the fuel cut happen for over 3 seconds.
- If a malfunction exists, the MIL will be indicated on the multi information display during step (f).

NOTE: If the conditions in this test are not strictly followed, detection of the malfunction will not be possible. If you do not have a hand-held tester, turn the ignition switch OFF after performing steps (c) to (f), and then perform steps (c) to (f) again.

INSPECTION PROCEDURE

HINT:
Hand-held tester only:
Narrowing down the trouble area is possible by performing "A/F CONTROL" ACTIVE TEST (heated oxygen sensor or other trouble areas can be distinguished).
Perform the ACTIVE TEST's A/F CONTROL operation.

HINT: "A/F CONTROL" is the ACTIVE TEST which changes the injection volume to -12.5 % or +25 %.

1. Connect the hand-held tester to the DLC3 on the vehicle.
2. Turn the ignition switch ON.
3. Warm up the engine by running the engine speed at 2,500 rpm for approximately 90 seconds.
4. Select the item "DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL".
5. Perform "A/F CONTROL" 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

NOTE: 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).

The following of A/F CONTROL procedure enables the technician to check and graph the voltage outputs of both the heated oxygen sensors.

To display the graph, enter the following menus: ACTIVE TEST / A/F CONTROL / USER DATA. Then select O2S B1S1 and O2S B1S2 by pressing YES. Finally, push ENTER and F4.

Step 1:

Step 2 - 3:

Step 4 - 5:

Step 6 - 7:

HINT: 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, as well as other data from the time when a malfunction occurred.

CHECK FOR INTERMITTENT PROBLEMS

Hand-held tester only:
Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect when the ECM is in check mode. In check mode, the ECM uses 1 trip detection logic, which has a higher sensitivity to malfunctions than normal mode (default), which uses 2 trip detection logic.

a. Clear the DTCs.
b. Change to check mode.
c. Perform a simulation test.
d. Check the connector and terminal.
e. Wiggle the harness and connector.