P0156
DTC P0136 Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)DTC P0138 Oxygen Sensor Circuit High Voltage (Bank 1 Sensor 2)
DTC P0139 Oxygen Sensor Circuit Slow Response (Bank 1 Sensor 2)
DTC P0156 Oxygen Sensor Circuit Malfunction (Bank 2 Sensor 2)
DTC P0158 Oxygen Sensor Circuit High Voltage (Bank 2 Sensor 2)
DTC P0159 Oxygen Sensor Circuit Slow Response (Bank 2 Sensor 2)
DESCRIPTION
DTC Detection Condition:
The heated oxygen sensor is used to monitor oxygen concentration in the exhaust gas. For optimum catalytic converter operation, the air-fuel mixture must be maintained near the ideal stoichiometric air-fuel ratio. The heated oxygen sensor output voltage changes suddenly in the vicinity of the stoichiometric air-fuel ratio. The ECM adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The heated oxygen sensor generates a voltage between 0.1 and 0.9 V in response to oxygen concentration in the exhaust gas.
If the oxygen concentration in the exhaust gas increases, the air-fuel ratio is called LEAN. The heated oxygen sensor voltage drops below 0.45 V, which informs the ECM of the LEAN condition.
If oxygen is not in the exhaust gas, the air-fuel ratio is called RICH. The heated oxygen sensor voltage increases above 0.45 V, which informs the ECM of the RICH condition.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
Component Operating Range:
The ECM monitors the heated oxygen sensor (sensor 2) to check if the following occurs:
- The heated oxygen sensor voltage does not remain RICH (above 0.5 V) or LEAN (below 0.4 V) while the vehicle is accelerating and decelerating 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 heated oxygen 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's voltage drops to below 0.2 V (extremely Lean status) immediately when the vehicle decelerates and fuel cut is operating. If the voltage does not drop to below 0.2 V, the ECM determines that the sensor's response feature has deteriorated, illuminates the MIL and sets a DTC.
MONITOR RESULT
Refer to CHECKING MONITOR STATUS. Mode 6 Data
CONFIRMATION DRIVING PATTERN
a. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
b. Switch the intelligent tester from normal mode to check mode.
c. Allow the engine to idle until the ECT reaches 75 °C (167 °F).
d. Allow the vehicle to run at 60 km/h (38 mph) or more for 20 seconds or more.
e. Allow the engine to idle for 10 seconds or more.
f. Perform the 2 previous steps at least 12 times.
HINT: If a malfunction exists, the MIL will be illuminated on the multi-information display.
NOTE: If the conditions in this test are not strictly followed, detection of a malfunction will not occur. If you do not have the intelligent tester, turn the ignition switch OFF after performing steps (c) to (f), then perform steps (c) to (f) again.
Wiring Diagram:
Step 1:
Step 1(Continued)-3:
Step 4-6:
Step 6(Continued)-8:
Step 9-11:
Step 11(Continued):
INSPECTION PROCEDURE
HINT: It is possible that the malfunctioning area can be found using the ACTIVE TEST A/F CONTROL operation. The ACTIVE TEST can determine if the heated oxygen sensor or other potential trouble areas are malfunctioning or not.
The injection volume can be switched to -12.5% (decrease) or +25% (increase) by the ACTIVE TEST.
The ACTIVE TEST procedure enables a technician to check and graph the output voltage of the heated oxygen sensors.
Procedure:
a. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.
b. Turn the ignition switch ON.
c. Warm up the engine by running the engine at 2,500 rpm for approximately 90 seconds.
d. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
e. Perform the ACTIVE TEST while the engine is idling.
Standard: The heated oxygen sensor reacts in accordance with the increase and decrease of injection volume:
+25% -> RICH output: More than 0.55 V
-12.5% -> LEAN output: Less than 0.4 V
NOTE: The heated oxygen sensor (sensor 1) output has a few seconds of delay and the heated oxygen sensor (sensor 2) output has a maximum of 20 seconds of delay.
If the vehicle is short on fuel, the air-fuel ratio becomes LEAN and the DTCs will be recorded.
HINT:
- Read freeze frame data using the intelligent tester. 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.
- Bank 1 refers to the bank that includes No. 1 cylinder.
- Bank 2 refers to the bank that does not include No. 1 cylinder.
- No. 1 cylinder is located in the front part of the engine, opposite the transmission.
- Sensor 2 refers to the sensor farthest away from the engine body.