P0136
4GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0136: Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)
DTC P0136 - Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)
DTC P0137 - Oxygen Sensor Circuit Low Voltage (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 P0157 - Oxygen Sensor Circuit Low Voltage (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
HINT:
Sensor 2 refers to the sensor mounted behind the three-way catalytic converter and located far from the engine assembly.
In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon and nitrogen oxide (NOx) components in the exhaust gas, a three-way catalytic converter is used. For the most efficient use of the three-way catalytic converter, the air fuel ratio must be precisely controlled so that it is always close to the stoichiometric air fuel level. For the purpose of helping the ECM to deliver accurate air fuel ratio control, a heated oxygen sensor is used.
The heated oxygen sensor is located behind the three-way catalytic converter, and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen concentration even when the intake air volume is low (the exhaust gas temperature is low).
When the air fuel ratio becomes lean, the oxygen concentration in the exhaust gas is rich. The heated oxygen sensor informs the ECM that the post-three-way catalytic converter air fuel ratio is lean (low voltage, i.e. less than 0.45 V).
Conversely, when the air fuel ratio is richer than the stoichiometric air fuel level, the oxygen concentration in the exhaust gas becomes lean. The heated oxygen sensor informs the ECM that the post-three-way catalytic converter air fuel ratio is rich (high voltage, i.e. more than 0.45 V). The heated oxygen sensor has the property of changing its output voltage drastically when the air fuel ratio is close to the stoichiometric level.
The ECM uses the supplementary information from the heated oxygen sensor to determine whether the air fuel ratio after the three-way catalytic converter is rich or lean, and adjusts the fuel injection time accordingly. Thus, if the heated oxygen sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air fuel ratio control.
*1: For USA and CANADA
*2: For KOREA
MONITOR DESCRIPTION
1. Active Air Fuel Ratio Control
The ECM usually performs air fuel ratio feedback control so that the air fuel ratio sensor output indicates a near stoichiometric air fuel level. This vehicle includes active air fuel ratio control in addition to regular air fuel ratio control. The ECM performs active air fuel ratio control to detect any deterioration in the three-way catalytic converter and heated oxygen sensor malfunctions (refer to the diagram below).
Active air fuel ratio control is performed for approximately 15 to 20 seconds while driving with a warm engine. During active air fuel ratio control, the air fuel ratio is forcibly regulated to become lean or rich by the ECM. If the ECM detects a malfunction, a DTC is set.
2. Abnormal Voltage Output of Heated Oxygen Sensor (DTC P0136 and P0156)
While the ECM is performing active air fuel ratio control, the air fuel ratio is forcibly regulated to become rich or lean. If the sensor is not functioning properly, the voltage output variation is small. For example, when the heated oxygen sensor voltage does not decrease to less than 0.21 V and does not increase to more than 0.59 V during active air fuel ratio control, the ECM determines that the sensor voltage output is abnormal and sets DTCs P0136.
3. Open or Short in Heated Oxygen Sensor Circuit (DTCs P0137 and P0157 or P0138 and P0158)
During active air fuel ratio control, the ECM calculates the oxygen storage capacity* of the three-way catalytic converter by forcibly regulating the air fuel ratio to become rich or lean.
If the heated oxygen sensor has an open or short, or the voltage output of the sensor noticeably decreases, the oxygen storage capacity indicates an extraordinarily high value. Even if the ECM attempts to continue regulating the air fuel ratio to become rich or lean, the heated oxygen sensor output does not change.
While performing active air fuel ratio control, when the target air fuel ratio is rich and the heated oxygen sensor voltage output is 0.21 V or less (lean), the ECM interprets this as an abnormally low sensor output voltage and sets DTC P0137. When the target air fuel ratio is lean and the voltage output is 0.59 V or more (rich) during active air fuel ratio control, the ECM determines that the sensor voltage output is abnormally high, and sets DTC P0138.
HINT:
DTC P0138 is also set if the heated oxygen sensor voltage output is more than 1.2 V for 10 seconds or more.
*: The three-way catalytic converter has the capability to store oxygen. The oxygen storage capacity and the emission purification capacity of the three-way catalytic converter are mutually related. The ECM determines whether the catalyst has deteriorated, based on the calculated oxygen storage capacity value P0420.
4. High or Low Impedance of Heated Oxygen Sensor (DTCs P0136 and P0156 or P0137 and P0157)
During normal air fuel ratio feedback control, there are small variations in the exhaust gas oxygen concentration. In order to continuously monitor the slight variation of the heated oxygen sensor signal while the engine is running, the impedance* of the sensor is measured by the ECM. The ECM determines that there is a malfunction in the sensor when the measured impedance deviates from the standard range.
*: The effective resistance in an alternating current electrical circuit.
- The impedance cannot be measured using an ohmmeter.
- DTCs P0136 indicate the deterioration of the heated oxygen sensor. The ECM sets the DTCs by calculating the impedance of the sensor when the typical enabling conditions are satisfied (2 driving cycles).
- DTCs P0137 indicate an open or short circuit in the heated oxygen sensor (2 driving cycles). The ECM sets the DTCs when the impedance of the sensor exceeds the threshold 15 kOhms.
5. Heated Oxygen Sensor Voltage Fuel Cut (P0139 or P0159)
The sensor output 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 for 7 seconds or more, or voltage does not drop from 0.35 V to 0.2 V for 1 second the ECM determines that the sensor's response feature has deteriorated, illuminates the MIL and sets a DTC.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
All:
Heated Oxygen Sensor Output Voltage (Output Voltage, High Voltage and Low Voltage):
Heated Oxygen Sensor Impedance (Low):
Heated Oxygen Sensor Impedance (High):
Heated Oxygen Sensor Output Voltage (Extremely High):
Heated oxygen sensor voltage during fuel cut:
TYPICAL MALFUNCTION THRESHOLDS
Heated Oxygen Sensor Output Voltage (Output voltage):
Heated Oxygen Sensor Output Voltage (Low output voltage):
Heated Oxygen Sensor Output Voltage (High output voltage):
Heated Oxygen Sensor Impedance (Low):
Heated Oxygen Sensor Impedance (High):
Heated Oxygen Sensor Output Voltage (Extremely High):
Heated Oxygen Sensor Voltage During Fuel-cut:
COMPONENT OPERATING RANGE
MONITOR RESULT
Refer to CHECKING MONITOR STATUS Mode 6 Data.
WIRING DIAGRAM
CONFIRMATION DRIVING PATTERN
HINT:
- This confirmation driving pattern is used in the "PERFORM CONFIRMATION DRIVING PATTERN" procedure of the following diagnostic troubleshooting procedure.
- Performing this confirmation driving pattern will activate the heated oxygen sensor monitor (The catalyst monitor is performed simultaneously). This is very useful for verifying the completion of a repair.
1 Connect Techstream to the DLC3.
2 Turn the engine switch on (IG).
3 Warm-up the engine until the engine coolant temperature reaches 75°C (167°F) or more [A].
4 Drive the vehicle at between 38 mph and 75 mph (60 km/h and 120 km/h) for at least 10 minutes [B].
5 Drive the vehicle 38 mph (60 km/h) or more and decelerate the vehicle for 10 seconds or more. Perform this 3 times [C].
6 Turn the tester on.
7 Select the following menu items: Powertrain / Engine and ECT / Utility / All Readiness.
8 Input DTCs: P0136, P0137, P0138, P0139, P0156, P0157, P0158 and P0159.
Check the DTC MONITOR is NORMAL. If DTC MONITOR is INCOMPLETE, perform the drive pattern adding the vehicle speed and using the second gear to decelerate the vehicle.
INSPECTION PROCEDURE
HINT:
Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F sensor function provided in the Active Test. The Control the Injection Volume for A/F sensor function can help to determine whether the air fuel ratio sensor, heated oxygen sensor and other potential trouble areas are malfunctioning.
The following instructions describe how to conduct the Control the Injection Volume for A/F sensor operation using a Techstream.
1 Connect Techstream to the DLC3.
2 Start the engine.
3 Turn the tester on.
4 Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
5 Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F sensor.
6 Perform the Active Test operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
7 Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS Voltage B1 S1 or AFS Voltage B2 S1 and O2S B1 S2 or O2S B2 S2) displayed on the tester.
HINT:
- The Control the Injection Volume for air fuel ratio sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.
- Each sensor reacts in accordance with increases and decreases in the fuel injection volume.
NOTE:
The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.
- Following the Control the Injection Volume for A/F sensor procedure enables technicians to check and graph the voltage outputs of both the air fuel ratio and heated oxygen sensors.
- To display the graph, select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS Voltage B1 S1 or AFS Voltage B2 S1 and O2S B1 S2 or O2S B2 S2 then press the graph button on the Data List view.
HINT:
- Read freeze frame data using Techstream. Freeze frame data records 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 OX1B or OX2B wire from the ECM connector is short-circuited to the +B wire, DTC P0136 or P0156 may be set.
PROCEDURE
1. READ DTC OUTPUT
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the tester on.
(d) Select the following menu items: Powertrain / Engine and ECT / Trouble Codes.
(e) Read DTCs.
Result:
D -- READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR)
C -- READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR)
B -- CHECK FOR EXHAUST GAS LEAK
A -- Continue to next step.
2. READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the tester on.
(d) Select the following menu items: Select: Powertrain / Engine and ECT / Data List / A/F Control System / O2S B1 S2 or O2S B2 S2.
(e) Allow the engine to idle.
(f) Read the heated oxygen sensor output voltage while idling.
Result:
B -- INSPECT AIR FUEL RATIO SENSOR
A -- Continue to next step.
3. INSPECT HEATED OXYGEN SENSOR (CHECK FOR SHORT)
(a) Disconnect the J68*1 or J40*2, Q4*3 HO2 sensor connector.
- *1: Bank 1 Sensor 2
- *2: Bank 2 Sensor 2 (2WD)
- *3: Bank 2 Sensor 2 (4WD)
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance (Bank 1 sensor 2):
Standard resistance (Bank 2 sensor 2):
NG -- REPLACE HEATED OXYGEN SENSOR
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT)
(a) Turn the engine switch off and wait for 5 minutes.
(b) Disconnect the A6 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
(d) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM
5. INSPECT AIR FUEL RATIO SENSOR
HINT:
This air fuel ratio sensor test is to check the air fuel ratio sensor current during the fuel-cut. When the sensor is normal, the sensor current will indicate below 3.0 mA in this test.
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the tester on.
(d) Drive the vehicle according to the drive pattern listed below:
(1) Warm up the engine until the engine coolant temperature reaches 75°C (167°F) or more.
(2) Drive the vehicle at 40 mph (60 km/h) or more and decelerate the vehicle for 5 seconds or more.
(3) Repeat the deceleration above at least 3 times.
(e) Select the following menu items: Select: Powertrain / Engine and ECT / Monitor / O2 Sensor / Details.
(f) Confirm that RANGE B1S1 is either Pass or Fail. If the tester shows Incomplete, re-check RANGE B1S1 after performing the drive pattern.
(g) Select the RANGE B1S1.
(h) Read the Test Value.
Standard current:
Less than 3.0 mA
HINT:
If the tester shows Incomplete again, add the vehicle speed and use the second gear to decelerate the vehicle. Refer to the CONFIRMATION DRIVING PATTERN.
NG -- REPLACE AIR FUEL RATIO SENSOR
OK -- REPLACE HEATED OXYGEN SENSOR
6. READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the tester on.
(d) Start the engine.
(e) Select the following menu items: Powertrain / Engine and ECT / Data List / A/F Control System / O2S B1 S2 or O2S B2 S2.
(f) After warming up the engine, run the engine at an engine speed of 2500 rpm for 3 minutes.
(g) Read the output voltage of the heated oxygen sensor when the engine rpm is suddenly increased.
HINT:
Quickly accelerate the engine to 4000 rpm 3 times using the accelerator pedal.
Standard:
Fluctuates between 0.4 V or less and 0.5 V or more.
NG -- CHECK FOR EXHAUST GAS LEAK
OK -- Continue to next step.
7. PERFORM ACTIVE TEST USING TECHSTREAM (INJECTION VOLUME)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the tester on.
(d) Start the engine and warm it up.
(e) Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Injection Volume.
(f) Change the fuel injection volume using the tester, and monitor the voltage output of air fuel ratio and heated oxygen sensors displayed on the tester.
HINT:
- Change the fuel injection volume within the range of -12% and +12%. The injection volume can be changed in 1% graduations within the range.
- The air fuel ratio sensor is displayed as AFS Voltage B1 S1 or AFS Voltage B2 S1, and the heated oxygen sensor is displayed as O2S B1 S2 or O2S B2 S2 on the Techstream.
Result:
HINT:
A normal heated oxygen sensor voltage (O2S B1 S2 or O2S B2 S2) reacts in accordance with increases and decreases in fuel injection volumes. When the air fuel ratio sensor voltage remains at either less or more than 3.3 V despite the heated oxygen sensor indicating a normal reaction, the air fuel ratio sensor is malfunctioning.
NG -- REPLACE AIR FUEL RATIO SENSOR
OK -- CHECK ENGINE TO DETERMINE CAUSE OF EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO
8. CHECK FOR EXHAUST GAS LEAK
OK:
No gas leak.
NG -- REPAIR OR REPLACE EXHAUST GAS LEAK POINT
OK -- Continue to next step.
9. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
(a) Disconnect the J68*1 or J40*2, Q4*3 HO2 sensor connector.
- *1 Bank 1 Sensor 2
- *2 Bank 2 Sensor 2 (2WD)
- *3 Bank 2 Sensor 2 (4WD)
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance (Bank 1 sensor 2):
Standard resistance (Bank 2 sensor 2):
NG -- REPLACE HEATED OXYGEN SENSOR
OK -- Continue to next step.
10. INSPECT INTEGRATION RELAY (EFI MAIN RELAY)
(a) Remove the integration relay from the engine room J/B No. 2.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:
(c) Reinstall the integration relay.
NG -- REPLACE INTEGRATION RELAY
OK -- Continue to next step.
11. CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)
(a) Disconnect the J68*1 and J40*2, Q4*3 HO2 sensor connector.
- *1: Bank 1 Sensor 2
- *2: Bank 2 Sensor 2 (2WD)
- *3: Bank 2 Sensor 2 (4WD)
(b) Turn the engine switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:
(d) Turn the engine switch off.
(e) Disconnect the A6 ECM connector.
(f) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):
Standard resistance (Check for short):
(g) Reconnect the HO2 sensor connector.
(h) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
12. REPLACE HEATED OXYGEN SENSOR
(a) Replace the heated oxygen sensor Removal.
NEXT -- Continue to next step.
13. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Warm-up the engine until the engine coolant temperature is 75°C (167°F) or more.
(c) Drive the vehicle at 38 to 75 mph (60 to 120 km/h) for at 10 minutes.
(d) Drive the vehicle 38 mph (60 km/h) or more and decelerate the vehicle for 10 seconds or more. Perform this 3 times.
(e) Turn the tester on.
(f) Select the following menu items: Powertrain / Engine and ECT / Utility / All Readiness.
(g) Input DTCs: P0136, P0137, P0138, P0156, P0157 and P0158.
(h) Check that DTC MONITOR is NORMAL. If DTC MONITOR is INCOMPLETE, perform the driving pattern increasing the vehicle speed and using the second gear to decelerate the vehicle.
Result:
B -- REPLACE AIR FUEL RATIO SENSOR
A -- END
14. REPLACE AIR FUEL RATIO SENSOR
(a) Replace the air fuel ratio sensor Removal.
NEXT -- Continue to next step.
15. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Warm-up the engine until the engine coolant temperature is 75°C (167°F) or more.
(c) Drive the vehicle at 38 to 75 mph (60 to 120 km/h) for at 10 minutes.
(d) Drive the vehicle 38 mph (60 km/h) or more and decelerate the vehicle for 10 seconds or more. Perform this 3 times.
(e) Turn the tester on.
(f) Select the following menu items: Powertrain / Engine and ECT / Utility / All Readiness.
(g) Input DTCs: P0136, P0137, P0138, P0156, P0157 and P0158.
(h) Check that DTC MONITOR is NORMAL. If DTC MONITOR is INCOMPLETE, perform the driving pattern increasing the vehicle speed and using the second gear to decelerate the vehicle.
Result:
B -- REPLACE HEATED OXYGEN SENSOR
A -- END
16. READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the tester on.
(d) Select the following menu items: Select: Powertrain / Engine and ECT / Data List / A/F Control System / O2S B1 S2 or O2S B2 S2.
(e) Allow the engine to idle.
(f) Read the heated oxygen sensor output voltage while idling.
Result:
B -- READ VALUE USING DTC OUTPUT (DTC P0139 OR P0159 IS OUTPUT AGAIN)
A -- Continue to next step.
17. INSPECT HEATED OXYGEN SENSOR
(a) Disconnect the J68*1 or J40*2, Q4*3 HO2 sensor connector.
- *1: Bank 1 Sensor 2
- *2: Bank 2 Sensor 2 (2WD)
- *3: Bank 2 Sensor 2 (4WD)
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance (Bank 1 sensor 2):
Standard resistance (Bank 2 sensor 2):
NG -- REPLACE HEATED OXYGEN SENSOR
OK -- Continue to next step.
18. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT)
(a) Turn the engine switch off and wait for 5 minutes.
(b) Disconnect the A6 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
(d) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM
19. READ VALUE USING DTC OUTPUT (DTC P0139 OR P0159 IS OUTPUT AGAIN)
(a) Connect the Techstream to the DLC3.
(b) Warm-up the engine until the engine coolant temperature is 75°C (167°F) or more.
(c) Drive the vehicle at 38 to 75 mph (60 to 120 km/h) for at 10 minutes.
(d) Drive the vehicle 38 mph (60 km/h) or more and decelerate the vehicle for 10 seconds or more. Perform this 3 times.
(e) Turn the tester on.
(f) Select the following menu items: Powertrain / Engine and ECT / Utility / All Readiness.
(g) Input DTCs: P0139 and P0159.
(h) Check that DTC MONITOR is NORMAL. If DTC MONITOR is INCOMPLETE, perform the driving pattern increasing the vehicle speed and using the second gear to decelerate the vehicle.
Result:
B -- REPLACE HEATED OXYGEN SENSOR
A -- CHECK FOR INTERMITTENT PROBLEMS