P0157
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
DTC Detection Condition:
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 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 volts 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 volts. 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 volts.
MONITOR DESCRIPTION
Monitor Strategy (Part 1):
Monitor Strategy (Part 2):
Typical Enabling Conditions (Part 1):
Typical Enabling Conditions (Part 2):
Typical Malfunction Thresholds:
Component Operating Range:
The ECM 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 6 seconds after fuel-cut is performed while the vehicle is decelerated. The ECM interprets this as the sensor response having deteriorated.
O2S TEST RESULT
If the sensor voltage is outside the standard values, the ECM interprets this as a malfunction and sets a DTC.
CONFIRMATION DRIVING PATTERN
1. Connect the intelligent tester to the DLC3.
2. Switch the ECM from normal mode to check mode using the tester.
3. Start the engine and warm it up until the engine coolant temperature reaches more than 75 degree C (167 degree F). (Procedure "A")
4. Drive the vehicle at 38 mph (60 km/h) or more for 40 seconds or more. (Procedure "B")
5. Let the engine idle for 10 seconds or more. (Procedure "C")
6. Perform procedure "A" and "C" 12 times. (Procedure "D")
HINT: If a malfunction exists, the MIL illuminates during procedure "D".
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 engine switch off after performing procedure from "A" to "D", then perform procedure "A" to "D" 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.
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. On the tester, enter the following menus: 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:
- 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.
Wiring Diagram:
Step 1-2:
Step 2(continued)-5:
Step 5(Continued)-7:
Step 7(Continued)-9:
Step 9(Continued)-12:
Step 13-15:
Step 15(Continued):
INSPECTION PROCEDURE
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 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 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.