Sfi System - P0158

1. Description

2. Monitor description

3. Monitor strategy

4. Typical enabling conditions

5. Typical malfunction thresholds

6. Component operating range

7. O2s test result

8. Wiring diagram

9. Confirmation driving pattern

10. Inspection procedure

11. Read dtc output

12. Read value of intelligent tester (output voltage of heated oxygen sensor)

13. Check harness and connector (check for short)

14. Inspect heated oxygen sensor (check for short)

15. Perform confirmation driving pattern

16. Check whether dtc output recurs (dtc p0138 or p0158)

17. Read value of intelligent tester (output voltage of heated oxygen sensor)

18. Perform confirmation driving pattern

19. Check whether dtc output recurs (dtc p0136 or p0156)

20. Replace heated oxygen sensor

21. Perform confirmation driving pattern

22. Check whether dtc output recurs (dtc p0136 or p0156)

23. Perform active test by intelligent tester (injection volume)

24. Check for exhaust gas leakage

25. Inspect heated oxygen sensor (heater resistance)

26. Inspect efi relay

27. Check harness and connector (heated oxygen sensor - ecm)

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 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)

HINT:

Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.

DESCRIPTION

MONITOR DESCRIPTION

1. The ECM usually performs air-fuel ratio feedback control so that the Air-Fuel Ratio (A/F) 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 (TWC) and Heated Oxygen (HO2) sensor malfunctions (refer to the diagram below).
   
2. 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.
   
3. If the ECM detects a malfunction, one of the following DTCs is set: DTC P0136 or P0156 (abnormal voltage output), P0137 or P0157 (open circuit) or P0138 or P0158 (short circuit).
   

1. 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 HO2 sensor voltage does not decrease to less than 0.21 V or 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 and P0156.
   
   
   
   
   
   

1. During active air-fuel ratio control, the ECM calculates the Oxygen Storage Capacity (OSC)* of the Three-Way Catalytic Converter (TWC) by forcibly regulating the air-fuel ratio to become rich or lean.
   
2. If the HO2 sensor has an open or short, or the voltage output of the sensor noticeably decreases, the OSC indicates an extraordinarily high value. Even if the ECM attempts to continue regulating the air-fuel ratio to become rich or lean, the HO2 sensor output does not change.
   
3. While performing active air-fuel ratio control, when the target air-fuel ratio is rich and the HO2 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 or P0157. 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 or P0158.
   

   HINT:

   DTC P0138 or P0158 is also set if the HO2 sensor voltage output is more than 1.2 V for 30 seconds or more.

   *: The TWC has the capability to store oxygen. The OSC and the emission purification capacity of the TWC are mutually related. The ECM determines whether the catalyst has deteriorated, based on the calculated OSC value (Click here).

   
   
   
   
   
   

1. 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 HO2 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.
   

   HINT:

   1. The impedance cannot be measured using an ohmmeter.
      
   2. DTCs P0136 and P0156 indicate the deterioration of the HO2 sensor. The ECM sets the DTCs by calculating the impedance of the sensor when the typical enabling conditions are satisfied (1 driving cycle).
      
   3. DTCs P0137 and P0157 indicate an open or short circuit in the HO2 sensor (1 driving cycle). The ECM sets the DTCs when the impedance of the sensor exceeds the threshold 15 kΩ.
      

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

O2S TEST RESULT

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

HINT:

1. This confirmation driving pattern is used in steps 5, 8 and 11 of the following diagnostic troubleshooting procedure when using the intelligent tester.
   
2. Performing this confirmation pattern will activate the Heated Oxygen (HO2) sensor monitor. (The catalyst monitor is performed simultaneously.) This is very useful for verifying the completion of a repair.
   

1. Connect the intelligent tester to the DLC3 (Procedure A).
   
2. Turn the ignition switch on (Procedure B).
   
3. Turn the tester on (Procedure C).
   
4. Clear DTCs (Click here) (Procedure D).
   
5. Select the following menu items: DIAGNOSIS / CARB OBD II / READINESS TESTS (Procedure E).
   
6. Check that O2S EVAL is INCMPL (incomplete) (Procedure F).
   
7. Start the engine and warm it up (Procedure G).
   
8. Drive the vehicle at between 40 mph and 70 mph (64 km/h and 113 km/h) for at least 10 minutes (Procedure H).
   
9. Note the state of the Readiness Tests items. Those items will change to COMPL (complete) as O2S EVAL monitor operates (Procedure I).
   
10. On the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / PENDING CODES and check if any DTCs (any pending DTCs) are set (Procedure J).
    

    HINT:

    If O2S EVAL does not change to COMPL, and any pending DTCs fail to set, extend the driving time.

INSPECTION PROCEDURE

HINT:

For use of the intelligent tester only:

Malfunctioning areas can be identified by performing the A/F CONTROL function provided in the ACTIVE TEST. The A/F CONTROL function can help to determine whether the Air-Fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the A/F CONTROL operation using the intelligent tester.

1. Connect the intelligent tester to the DLC3.
   
2. Start the engine and turn the tester on.
   
3. Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
   
4. Select the following menu items on the tester: 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 to change the fuel injection volume).
   
6. Monitor the voltage outputs of the A/F and HO2 sensors (AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2) displayed on the tester.
   

   HINT:

   1. The A/F CONTROL operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.
      
   2. Each sensor reacts in accordance with increases and decreases in the fuel injection volume.
      
   
   

   Standard voltage:

   
   

   Tester Display (Sensor)	Injection Volumes	Status	Voltages
   AFS B1S1 or AFS B2S1 (A/F)	+25%	Rich	Less than 3.0
   AFS B1S1 or AFS B2S1 (A/F)	-12.5%	Lean	More than 3.35
   O2S B1S2 or O2S B2S2 (HO2)	+25%	Rich	More than 0.55
   O2S B1S2 or O2S B2S2 (HO2)	-12.5%	Lean	Less than 0.4

   NOTICE:

   The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and the Heated Oxygen (HO2) sensor has a maximum output delay of approximately 20 seconds.

   
   

   Case	A/F Sensor (Sensor 1) Output Voltage		HO2 Sensor (Sensor 2) Output Voltage		Main Suspected Trouble Area
   1	Injection Volume +25% -12.5%		Injection Volume +25% -12.5%		-
   	Output Voltage More than 3.35 V Less than 3.0 V		Output Voltage More than 0.55 V Less than 0.4 V
   2	Injection Volume +25% -12.5%		Injection Volume +25% -12.5%		A/F sensor A/F sensor heater A/F sensor circuit
   	Output Voltage Almost no reaction		Output Voltage More than 0.55 V Less than 0.4 V
   3	Injection Volume +25% -12.5%		Injection Volume +25% -12.5%		HO2 sensor HO2 sensor heater HO2 sensor circuit
   	Output Voltage More than 3.35 V Less than 3.0 V		Output Voltage Almost no reaction
   4	Injection volume +25 % -12.5%		Injection Volume +25% -12.5%		Injector Fuel pressure Gas leakage from exhaust system (Air-fuel ratio extremely lean or rich)
   	Output Voltage Almost no reaction		Output Voltage Almost no reaction

7. 1. Following the A/F CONTROL procedure enables technicians to check the graph of the voltage outputs of both the A/F and HO2 sensors.
      
   2. To display the graph, select the following menu items on the tester: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2. Press the YES button and then the ENTER button. Then press the F4 button.
      

      HINT:

      1. If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
         
      2. Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
         
      3. If the OX1B wire from the ECM connector is short-circuited to the +B wire, DTC P0136 will be set.
         
      4. If the OX2B wire from the ECM connector is short-circuited to the +B wire, DTC P0156 will be set.
         

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch on and turn the tester on.

3. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

4. Read DTCs.
   

   Result:

   
   

   Display (DTC Output)	Proceed to
   P0138 or P0158	A
   P0137 or P0157	B
   P0136 or P0156	C

B	Go to step 14
C	Go to step 7

A

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch on and turn the tester on.

3. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / PRIMARY / O2S B1S2 or O2S B2S2.

4. Allow the engine to idle.

5. Read the Heated Oxygen (HO2) sensor output voltage while idling.
   

   Result:

   
   

   HO2 Sensor Output Voltages	Proceed to
   More than 1.2 V	A
   Less than 1.0 V	B

B	Go to step 5

A

1. Turn the ignition switch off and wait for 5 minutes.

2. Disconnect the E4 or E5 ECM connector.

3. Measure the resistance.

   Standard resistance:

   Tester Connections	Specified Conditions
   HT1B (E4-1) - OX1B (E4-18)	10 kΩ or higher
   HT2B (E5-5) - OX2B (E5-33)	10 kΩ or higher

4. Reconnect the ECM connector.

NG	Go to step 4

OK
REPLACE ECM

1. Disconnect the H6 or H8 Heated Oxygen (HO2) sensor connector.

2. Measure the resistance between the terminals of the HO2 sensor connector.
   

   Standard resistance:

   Bank 1:

   Tester Connections	Specified Conditions
   +B (2) - E1 (4)	10 kΩ or higher
   +B (2) - OX (3)	10 kΩ or higher

   Bank 2::

   Tester Connections	Specified Conditions
   +B (2) - E1 (4)	10 kΩ or higher
   +B (2) - OX (3)	10 kΩ or higher

3. Reconnect the HO2 sensor connector.

NG	REPLACE HEATED OXYGEN SENSOR

OK
REPAIR OR REPLACE HARNESS OR CONNECTOR

1. Perform confirmation driving pattern (Click here).

NEXT

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch on and turn the tester on.

3. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

4. Read DTCs.
   

   Result:

   
   

   Display (DTC Output)	Proceed to
   P0138 or P0158	A
   No output	B

B	CHECK FOR INTERMITTENT PROBLEMS

A
REPLACE HEATED OXYGEN SENSOR

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch on and turn the tester on.

3. Start the engine.

4. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / O2S B1S2 or O2S B1S2.

5. After warming up the engine, run the engine at an engine speed of 2,500 rpm for 3 minutes.

6. Read the output voltage of the HO2 sensor when the engine rpm is suddenly increased.

   HINT:

   Quickly accelerate the engine to 4,000 rpm 3 times using the accelerator pedal.

   Standard:

   Fluctuates between 0.4 V or less and 0.5 V or more.
   

NG	Go to step 14

OK

1. Perform confirmation driving pattern (Click here).

NEXT

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch on and turn the tester on.

3. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

4. Read DTCs.
   

   Result:

   
   

   Display (DTC Output)	Proceed to
   P0136 or P0156	A
   No output	B

B	CHECK FOR INTERMITTENT PROBLEMS

A

1. Replace the heated oxygen sensor (Click here).

NEXT

1. Perform confirmation driving pattern (Click here).

NEXT

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch on and turn the tester on.

3. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

4. Read DTCs.
   

   Result:

   
   

   Display (DTC Output)	Proceed to
   P0136 or P0156	A
   No output	B

B	REPAIR COMPLETED

A

1. Connect the intelligent tester to the DLC3.

2. Start the engine and turn the tester on.

3. Warm up the engine.

4. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / INJ VOL.

5. Change the fuel injection volume using the tester, monitoring the voltage output of Air-Fuel Ratio (A/F) and HO2 sensors displayed on the tester.

   HINT:

   1. Change the fuel injection volume within the range of -12% and +12%. The injection volume can be changed in 1% graduations within the range.
      
   2. The A/F sensor is displayed as AFS B1S1 or AFS B2S1, and the HO2 sensor is displayed as O2S B1S2 or O2S B2S2, on the intelligent tester.
      
   
   

   Result:

   
   

   Tester Display (Sensor)	Voltage Variations	Proceed to
   AFS B1S1 (A/F) AFS B2S1 (A/F)	Alternates between more and less than 3.3 V	OK
   AFS B1S1 (A/F) AFS B2S1 (A/F)	Remains at more than 3.3 V	NG
   AFS B1S1 (A/F) AFS B2S1 (A/F)	Remains at less than 3.3 V	NG

   HINT:

   A normal HO2 sensor voltage (O2S B1S2 or O2S B2S2) reacts in accordance with increases and decreases in fuel injection volumes. When the A/F sensor voltage remains at either less or more than 3.3 V despite the HO2 sensor indicating a normal reaction, the A/F sensor is malfunctioning.

   
   
   
   

NG	REPLACE AIR FUEL RATIO SENSOR

OK
CHECK AND REPLACE EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO (INJECTOR, FUEL PRESSURE, GAS LEAKAGE FROM EXHAUST SYSTEM,ETC)

OK:

No gas leakage.

NG	REPAIR OR REPLACE EXHAUST GAS LEAKAGE POINT

OK

1. Disconnect the H6 or H8 Heated Oxygen (HO2) sensor connector.

2. Measure the resistance between the terminals of the HO2 sensor connector.
   

   Standard resistance:

   Bank 1:

   Tester Connections	Specified Conditions
   HT (1) - +B (2)	11 to 16 Ω at 20°C (68°F)
   HT (1) - E1 (4)	10 kΩ or higher

   Bank 2:

   Tester Connections	Specified Conditions
   HT (1) - +B (2)	11 to 16 Ω at 20°C (68°F)
   HT (1) - E1 (4)	10 kΩ or higher

3. Reconnect the HO2 sensor connector.

NG	REPLACE HEATED OXYGEN SENSOR

OK

1. Remove the EFI relay from the engine room R/B.

2. Measure the EFI relay resistance.

   Standard resistance:

   Tester Connections	Specified Conditions
   3 - 5	10 kΩ or higher
   3 - 5	Below 1 Ω (when battery voltage applied to terminals 1 and 2)

3. Reinstall the EFI relay.

NG	REPLACE EFI RELAY

OK

1. Disconnect the H6 or H8 HO2 sensor connector.

2. Turn the ignition switch on.

3. Measure the voltage between the +B terminal of the HO2 sensor connector and body ground.

   Standard voltage:

   Tester Connections	Specified Conditions
   +B (H6-2) - Body ground	9 V to 14 V
   +B (H8-2) - Body ground	9 V to 14 V

4. Turn the ignition switch off.

5. Disconnect the E4 and E5 ECM connectors.

6. Measure the resistance.

   Standard resistance (Check for open):

   Tester Connections	Specified Conditions
   HT (H6-1) - HT1B (E4-1)	Below 1 Ω
   OX (H6-3) - OX1B (E4-18)	Below 1 Ω
   E1 (H6-4) - E2 (E4-28)	Below 1 Ω
   HT (H8-1) - HT2B (E5-5)	Below 1 Ω
   OX (H8-3) - OX2B (E5-33)	Below 1 Ω
   E1 (H8-4) - E2 (E4-28)	Below 1 Ω

   Standard resistance (Check for short):

   Tester Connections	Specified Conditions
   HT (H6-1) or HT1B (E4-1) - Body ground	10 kΩ or higher
   OX (H6-3) or OX1B (E4-18) - Body ground	10 kΩ or higher
   E1 (H6-4) or E2 (E4-28) - Body ground	10 kΩ or higher
   HT (H8-1) or HT2B (E5-5) - Body ground	10 kΩ or higher
   OX (H8-3) or OX2B (E5-33) - Body ground	10 kΩ or higher
   E1 (H8-4) or E2 (E4-28) - Body ground	10 kΩ or higher

7. Reconnect the HO2 sensor connector.

8. Reconnect the ECM connectors.

   
   
   
   

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
REPLACE HEATED OXYGEN SENSOR