P0156

3UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0136-P0139,P0156-P0159: Oxygen Sensor Circuit Malfunction (Bank 1 Sensor 2)
P0159 - Oxygen Sensor Circuit Slow Response (Bank 2 Sensor 2)

DESCRIPTION

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

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 0.5 V (rich) or below 0.4 V (lean) while the vehicle is accelerated and decelerated for 6 minutes or more.

- The HO2 sensor output voltage remains extremely low, below 0.05 V for a long time period of time while the vehicle is driven.

- The HO2 sensor output voltage lower than 0.03 V for 90 seconds.

- The HO2 sensor output voltage exceeds more than 1.2 V for 10 seconds.

- The HO2 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 within 6 seconds, or does not drop from 0.35 V to 0.2 V within 1 second, the ECM determines that the sensor response has deteriorated.

MONITOR STRATEGY

Crack:

Output voltage:

Low voltage:

Out of range:

Voltage during fuel-cut:

TYPICAL ENABLING CONDITIONS

All:

Heated oxygen sensor output voltage (crack):

Heated oxygen sensor output voltage:

Heated oxygen sensor low voltage:

Heated oxygen sensor out of range:

Heated oxygen sensor voltage during fuel cut:

TYPICAL MALFUNCTION THRESHOLDS

Heated oxygen sensor output voltage (crack):

Heated oxygen sensor output voltage:

Heated oxygen sensor low voltage:

Heated oxygen sensor out of range:

Heated oxygen sensor voltage during fuel cut:

COMPONENT OPERATING RANGE

MONITOR RESULT

Refer to CHECKING MONITOR STATUS Mode 6 Data.

CONFIRMATION DRIVING PATTERN

P0136, P0137, P0138, P0156, P0157 and P0158

- Connect the Techstream to the DLC3.

- Turn the ignition switch to ON and turn the Techstream on.

- Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).

- Turn the ignition switch off and wait for at least 30 seconds.

- Turn the ignition switch to ON and turn the Techstream on [A].

- Start the engine and warm it up until the ECT reaches 75°C (167°F) or higher [B].

- Drive the vehicle at 60 km/h (40 mph) or more for 6 minutes or more [C].

CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.

- Enter the following menus: Powertrain / Engine / Trouble Codes [D].

- Read the pending DTCs.

HINT
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
- Enter the following menus: Powertrain / Engine / Utility / All Readiness.

- Input the DTC: P0136, P0137, P0138, P0156, P0157 or P0158.

- Check the DTC judgment result.

HINT
If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [C] through [D].

- If no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.

P0139 and P0159

- Connect the Techstream to the DLC3.

- Turn the ignition switch to ON and turn the Techstream on.

- Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).

- Turn the ignition switch off and wait for at least 30 seconds.

- Turn the ignition switch to ON and turn the Techstream on [A].

- Start the engine and warm it up until the ECT reaches 75°C (167°F) or higher [B].

- Drive the vehicle at 60 km/h (40 mph), and then decelerate the vehicle by releasing the accelerator pedal for 7 seconds or more to perform the fuel-cut [C].

CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.

- Enter the following menus: Powertrain / Engine / Trouble Codes [D].

- Read the DTCs.

HINT
- If a pending DTC or current DTC is output, the system is malfunctioning.
- If a pending DTC or current DTC is not output, perform the following procedure.
- Enter the following menus: Powertrain / Engine / Utility / All Readiness.

- Input the DTC: P0139 or P0159.

- Check the DTC judgment result.

HINT
If the judgment result shows INCOMPLETE or UNKNOWN, shift the transmission to 2nd gear, and then perform steps [C] and [D] again.

- If no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.
WIRING DIAGRAM

INSEPCTION PROCEDURE

HINT
It is possible that the malfunctioning area can be found using the Active Test Control the Injection Volume to A/F Sensor 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 voltages of the heated oxygen sensors.

- Procedure:

- Connect the Techstream to the DLC3.

- Turn the ignition switch to ON.

- Warm up the engine by running the engine at 2500 rpm for approximately 90 seconds.

- Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor.

- 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

NOTICE:
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.

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT
- Read freeze frame data using the Techstream. 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 includes No. 1 cylinder, but bank 2 does not. The No. 1 cylinder is located in the front part of the engine, opposite the transmission.
- Sensor 1 refers to the sensor closest to the engine body.
- Sensor 2 refers to the sensor farthest away from the engine body.
PROCEDURE

1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0136, P0137, P0138, P0139, P0156, P0157, P0158, P0159)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Read the DTCs.

Result:

HINT
If any other codes besides P0136, P0137, P0138, P0139, P0156, P0157, P0158 and P0159 are output, perform the troubleshooting for those DTCs first.

D -- READ VALUE USING TECHSTREAM (HEATED OXYGEN SENSOR (SENSOR 2) VOLTAGE)

C -- READ VALUE USING TECHSTREAM (HEATED OXYGEN SENSOR (SENSOR 2) VOLTAGE)

B -- CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR (SENSOR 2) - ECM)
A -- Continue to next step.

2. READ VALUE USING TECHSTREAM (HEATED OXYGEN SENSOR (SENSOR 2) VOLTAGE)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / O2S B1S2 or O2S B2S2.

(e) Allow the engine to run at 2500 rpm for 3 minutes.

(f) Depress the accelerator pedal quickly until the engine rpm reaches 4,000 rpm 3 times.

Standard Voltage:

The heated oxygen sensor voltage alternates from below 0.4 V to 0.55 V or more.

Result:

B -- PERFORM CONFIRMATION DRIVING PATTERN
A -- Continue to next step.

3. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

(a) Disconnect the heated oxygen sensor connectors.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Standard Resistance (Check for Short):

NG -- REPLACE HEATED OXYGEN SENSOR
OK -- Continue to next step.

4. INSPECT EFI RELAY

(a) Remove the EFI relay from the engine room No. 2 relay block.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

NG -- REPLACE EFI RELAY
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR (SENSOR 2) - ECM)

(a) Disconnect the heated oxygen sensor connectors.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Standard Resistance (Check for Short):

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE HEATED OXYGEN SENSOR

6. PERFORM CONFIRMATION DRIVING PATTERN

HINT
Refer to the confirmation driving pattern for P0136, P0137, P0138, P0156, P0157 and P0158.

NEXT -- Continue to next step.

7. READ OUTPUT DTC (DTC P0136, P0137, P0138, P0156, P0157 AND P0158 IS OUTPUT AGAIN)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Utility / All Readiness.

(e) Input DTCs: P0136, P0137, P0138, P0156, P0157 and P0158.

- Check that the DTC monitor is NORMAL. If DTC monitor is INCOMPLETE, perform the drive pattern increasing the vehicle speed and using the second gear to decelerate the vehicle.

Result:

B -- CHECK FOR INTERMITTENT PROBLEMS

A -- REPLACE HEATED OXYGEN SENSOR

8. READ VALUE USING TECHSTREAM (HEATED OXYGEN SENSOR (SENSOR 2) VOLTAGE)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / O2S B1S2 or O2S B2S2.

(e) Allow the engine to run at 2500 rpm for 3 minutes.

(f) Depress the accelerator pedal quickly until the engine rpm reaches 4000 rpm 3 times.

Result:

B -- PERFORM CONFIRMATION DRIVING PATTERN
A -- Continue to next step.

9. CHECK HARNESS AND CONNECTOR (FOR SHORT)

NG -- INSPECT HEATED OXYGEN SENSOR

OK -- REPLACE ECM Service and Repair

10. INSPECT HEATED OXYGEN SENSOR

(a) Disconnect the heated oxygen sensor connectors.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Standard Resistance (Check for Short):

NG -- REPLACE HEATED OXYGEN SENSOR

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - HEATED OXYGEN SENSOR)

11. PERFORM CONFIRMATION DRIVING PATTERN

HINT
Refer to the confirmation driving pattern for P0136, P0137, P0138, P0156, P0157 and P0158.

NEXT -- Continue to next step.

12. READ OUTPUT DTC (DTC P0136, P0137, P0138, P0156, P0157 OR P0158 IS OUTPUT AGAIN)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Utility / All Readiness.

(e) Input DTCs: P0136, P0137, P0138, P0156, P0157 and P0158.

- Check that the DTC monitor is NORMAL. If DTC monitor is INCOMPLETE, perform the drive pattern increasing the vehicle speed and using the second gear to decelerate the vehicle.

Result:

B -- CHECK FOR INTERMITTENT PROBLEMS

A -- REPLACE HEATED OXYGEN SENSOR

13. READ VALUE USING TECHSTREAM (HEATED OXYGEN SENSOR (SENSOR 2) VOLTAGE)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / O2S B1S2 or O2S B2S2.

(e) Allow the engine to run at 2500 rpm for 3 minutes.

(f) Depress the accelerator pedal quickly until the engine rpm reaches 4000 rpm 3 times.

Result:

B -- PERFORM CONFIRMATION DRIVING PATTERN
A -- Continue to next step.

14. CHECK HARNESS AND CONNECTOR (FOR SHORT)

NG -- INSPECT HEATED OXYGEN SENSOR

OK -- REPLACE ECM Service and Repair

15. INSPECT HEATED OXYGEN SENSOR

(a) Disconnect the heated oxygen sensor connectors.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Standard Resistance (Check for Short):

NG -- REPLACE HEATED OXYGEN SENSOR

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - HEATED OXYGEN SENSOR)

16. PERFORM CONFIRMATION DRIVING PATTERN

HINT
Refer to the confirmation driving pattern for P0139 and P0159.

NEXT -- Continue to next step.

17. READ DTC OUTPUT (DTC P0139 OR P0159 IS OUTPUT AGAIN))

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Utility / All Readiness.

(e) Input DTCs: P0139 and P0159.

- Check that the DTC monitor is NORMAL. If DTC monitor is INCOMPLETE, perform the drive pattern increasing the vehicle speed and using the second gear to decelerate the vehicle.

Result:

B -- CHECK FOR INTERMITTENT PROBLEMS

A -- REPLACE HEATED OXYGEN SENSOR