P0158

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)

DESCRIPTION
The heated oxygen sensor (HO2S) is used to monitor oxygen in the exhaust gas. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal "stoichiometric" ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. The ECM (Included in HV control ECU) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric.

The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes "Lean". The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes "Rich". The ECM interprets Rich when the HO2S voltage is above 0.45 V.

DTC Detection Condition:

MONITOR DESCRIPTION
The ECM (Included in HV control ECU) monitors the rear Heated Oxygen (HO2) sensor to check for the following malfunctions. If any of the malfunctions are detected, the ECM illuminates the MIL and sets a DTC.
- The HO2 sensor output voltage remains above 0.45 V (rich) or below 0.45 V (lean) while the vehicle is accelerated and decelerated for 8 minutes.
- The HO2 sensor output voltage remains at below 0.05 V, for a long period of time while the vehicle is driven.
- The HO2 sensor output voltage does not decrease below 0.2 V (extremely lean condition) within 7 seconds after fuel-cut is performed while the vehicle is decelerated. The ECM interprets this as the sensor response having deteriorated.

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds (Part 1):

Typical Malfunction Thresholds (Part 2):

Component Operating Range:

MONITOR RESULT

Refer to CHECKING MONITOR STATUS. Mode 6 Data

The test value and test limit information are described as shown in the following table. Check the monitor result and test values after performing the monitor drive pattern (refer to "Confirmation Monitor").
- MID (Monitor Identification Date) is assigned to each emission-related component.
- TID (Test Identification Date) is assigned to each test value.
- Scaling is used to calculate the test value indicated on generic OBD II scan tools.





If the sensor voltage is outside the standard values, the ECM (Included in HV control ECU) interprets this as a malfunction and sets a DTC.

Wiring Diagram:

CONFIRMATION DRIVING PATTERN




a. Connect the intelligent tester to the DLC3.
b. Switch the ECM (Included in HV control ECU) from normal mode to check mode using the tester.
c. Start the engine and warm it up until the engine coolant temperature reaches more than 75°C (167°F).
d. Drive the vehicle at 38 mph (60 km/h) or more for 40 seconds or more.
e. Let the engine idle for 10 seconds or more.
f. Perform steps (d) and (e) 12 times.

HINT: If a malfunction exists, the MIL illuminates during step (f).

NOTE: If the conditions in this test are not strictly followed, malfunctions may not be detected. If you do not have the intelligent tester, turn the ignition switch off after performing steps from (c) to (f), then perform steps (c) to (f) again.

CONFIRMATION DRIVING PATTERN

Warm up the engine and run the engine at 38 mph (60 km/h) for 7 minutes.

CONFIRMATION DRIVING PATTERN

Warm up the engine and run the engine at idle for 30 seconds.

INSPECTION PROCEDURE

HINT: 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 an 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 engine speed of 2,500 rpm for approximately 90 seconds.
4. Put the engine in inspection mode.
5. On the tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
6. 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).
7. 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:
- The A/F CONTROL operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.
- Each sensor reacts in accordance with increases in the fuel injection volume.





NOTE:
- 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.








- Following the A/F CONTROL procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.
- To display the graph, enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2, and press the YES button and then the ENTER button followed by the F4 button.

HINT:
- 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.
- Read freeze frame data using the intelligent tester. The ECM (Included in HV control ECU) records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.
- If the OX1B wire from the ECM (Included in HV control ECU) connector is short-circuited to the +B wire, DTC P0136 will be set.
- If the OX2B wire from the ECM connector is short-circuited to the +B wire, DTC P0156 will be set.

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