P2195

2ZR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2195, P2196: Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1)


DESCRIPTION

The A/F sensor generates a voltage* that corresponds to the actual air-fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air-fuel ratio. The ECM determines the deviation from the stoichiometric air-fuel ratio level, and regulates the fuel injection time. If the A/F sensor malfunctions, the ECM is unable to control the air-fuel ratio accurately.

The A/F sensor is the planar type and is integrated with the heater, which heats the solid electrolyte (zirconia element). This heater is controlled by the ECM. When the intake air volume is low (the exhaust gas temperature is low), a current flows into the heater to heat the sensor, in order to facilitate accurate oxygen concentration detection. In addition, the sensor and heater portions are the narrow type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, and therefore the sensor activation is accelerated.

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a TWC is used. For the most efficient use of the TWC, the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric level.

*: Value changes inside the ECM. Since the A/F sensor is the current output element, a current is converted into a voltage inside the ECM. Any measurements taken at the A/F sensor or ECM connectors will show a constant voltage.

HINT
- Although the DTC titles say oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.
- Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.









HINT
- When any of these DTCs are set, check the A/F sensor voltage output by selecting the following menu items on the Techstream: Powertrain / Engine and ECT / Data List / All Data / AFS Voltage B1S1.
- Short-term fuel trim values can also be read using the Techstream.
- The ECM regulates the voltages at the A1A+ and A1A- terminals of the ECM to a constant level. Therefore, the A/F sensor voltage output cannot be confirmed without using the Techstream.
- If a A/F sensor malfunction is detected, the ECM sets a DTC.

MONITOR DESCRIPTION

Sensor voltage detection monitor

Under the air fuel ratio feedback control, if the air fuel ratio sensor voltage output indicates rich or lean for a certain period of time, the ECM determines that there is a malfunction in the air fuel ratio sensor. The ECM illuminates the MIL and stores a DTC.

Example:

If the air fuel ratio sensor voltage output is below 2.8 V (very rich condition) and heated oxygen sensor output voltage falls from 0.59 V or more to less than 0.21 V for 5 seconds, the ECM stores DTC P2196. Alternatively, if the air fuel ratio sensor voltage output is higher than 3.8 V (very lean condition) and heated oxygen sensor output voltage rises from less than 0.21 V to 0.59 V or more for 5 seconds, DTC P2195 is stored.

Sensor current detection monitor

A rich air-fuel mixture causes a low A/F sensor current, and a lean air-fuel mixture causes a high A/F sensor current. Therefore, the sensor output becomes low during acceleration, and it becomes high during deceleration with the throttle valve fully closed. The ECM monitors the A/F sensor current during fuel-cut and detects any abnormal current values.

If the A/F sensor output is 2.2 mA or more for more than 3 seconds of cumulative time, the ECM interprets this as a malfunction in the A/F sensor and sets DTC P2195 (high-side stuck). If the A/F sensor output is less than 0.7 mA for more than 3 seconds of cumulative time, the ECM sets DTC P2196 (low-side stuck).





MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

ALL





Sensor voltage detection monitor (Lean side malfunction P2195):





Sensor voltage detection monitor (Rich side malfunction P2196):





Sensor current detection monitor (P2195, P2196):





TYPICAL MALFUNCTION THRESHOLDS

Sensor voltage detection monitor (Lean side malfunction P2195):





Sensor voltage detection monitor (Rich side malfunction P2196):





Sensor current detection monitor (High side malfunction P2195):





Sensor current detection monitor (Low side malfunction P2196):





MONITOR RESULT

Refer to CHECKING MONITOR STATUS Mode 6 Data.

CONFIRMATION DRIVING PATTERN

CAUTION:
Strictly observe posted speed limits, traffic laws, and road conditions when performing these drive patterns.

HINT
This confirmation driving pattern is used in the "PERFORM CONFIRMATION DRIVING PATTERN" procedure of the following diagnostic troubleshooting procedure.









1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the Techstream on.

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

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

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

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

8. On the Techstream, enter the following menus to check the fuel-cut status: Powertrain / Engine and ECT / Data List / Idle Fuel Cut.

9. Drive the vehicle at between 60 and 120 km/h (38 and 75 mph) for at least 10 minutes [B].

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

10. Shift the transmission to 2nd gear [C].

11. Accelerate the vehicle to 64 km/h (40 mph) or more by depressing the accelerator pedal for at least 10 seconds [D].

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

12. Soon after performing step [D] above, release the accelerator pedal for at least 4 seconds without depressing the brake pedal in order to execute fuel-cut control [E].

HINT
Fuel-cut is performed when the following conditions are met:

- Accelerator pedal is fully released.
- Engine speed is 2500 rpm or more (fuel injection returns at 1000 rpm).

13. Allow the vehicle to decelerate until the vehicle speed decreases to less than 10 km/h (6 mph).

14. Repeat steps [C] through [E] above at least 3 times in one driving cycle.

15. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [F].

16. 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.

17. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

18. Input the DTC: P2195 or P2196.

19. Check the DTC judgment result.





HINT
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [B] through [F] again.

20. 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





INSPECTION PROCEDURE

HINT
Malfunctioning areas can be identified by performing the Control the Injection Volume function provided in the Active Test. The Control the Injection Volume 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 Control the Injection Volume operation using the Techstream.

(a) Connect the Techstream to the DLC3.
(b) Start the engine.
(c) Turn the Techstream on.
(d) Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
(e) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume.
(f) Perform the Active Test operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume.)
(g) Monitor the output voltages of the A/F and HO2 sensors (AFS Voltage B1S1 and O2S B1S2) displayed on the tester.

HINT
- Change the fuel injection volume within the range of -12% to +12%. The injection volume can be changed in fine gradations.
- Each sensor reacts in accordance with increases and decreases in the fuel injection volume.





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.





- Following the Control the Injection Volume 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: Powertrain / Engine and ECT / Active Test / Control the Injection Volume / All Data / AFS Voltage B1S1 and O2S B1S2; then press the graph button on the Data List view.

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 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.
- A low A/F sensor voltage could be caused by a rich air fuel mixture. Check for conditions that would cause the engine to run rich.
- A high A/F sensor voltage could be caused by a lean air fuel mixture. Check for conditions that would cause the engine to run lean.

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P2195 OR P2196)

(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 and ECT / Trouble Codes.

(e) Read DTCs.

Result





HINT
If any DTCs other than P2195 and P2196 are output, troubleshoot those DTCs first.

B -- GO TO DTC CHART Engine Control System - SFI System
A -- Continue to next step.

2. CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST

(a) Has the vehicle run out of fuel in the past?

NO -- READ VALUE USING TECHSTREAM (TEST VALUE OF AIR FUEL RATIO SENSOR)
YES -- Continue to next step.

3. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear DTCs Reading and Clearing Diagnostic Trouble Codes.

(e) Turn the ignition switch off and wait for at least 30 seconds.

(f) Turn the ignition switch to ON.

(g) Turn the Techstream on.

(h) Start the engine and warm it up.

(i) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(j) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

(k) Input the DTC: P2195 or P2196.

(l) Check the DTC judgment.

Result





B -- READ VALUE USING TECHSTREAM (TEST VALUE OF AIR FUEL RATIO SENSOR)

A -- DTC CAUSED BY RUNNING OUT OF FUEL

4. READ VALUE USING TECHSTREAM (TEST VALUE OF AIR FUEL RATIO SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear DTCs Reading and Clearing Diagnostic Trouble Codes.

(e) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(f) Enter the following menus: Powertrain / Engine and ECT / Monitor / Current Monitor / O2 Sensor / Current.

(g) Check that the status of O2 Sensor is Complete.

If the status is still Incomplete, drive the vehicle according to the driving pattern again.

(h) Enter the following menus: Powertrain / Engine and ECT / Monitor / Current Monitor / O2 Sensor / Details / RANGE B1S1 or RANGE B2S1.

(i) Check the test value of the air fuel ratio sensor output current during fuel-cut.

Result





B -- REPLACE AIR FUEL RATIO SENSOR
A -- Continue to next step.

5. PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE INJECTION VOLUME)

(a) Connect the Techstream to the DLC3.

(b) Start the engine.

(c) Turn the Techstream on.

(d) Warm up the engine and run the engine at an engine speed of 2500 rpm for approximately 90 seconds.

(e) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume.

(f) Perform the Control the Injection Volume operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).

(g) Monitor the voltage outputs of the air fuel ratio sensor and the heated oxygen sensor (AFS Voltage B1S1 and O2S B1S2) displayed on the Techstream.

HINT
- Change the fuel injection volume within the range of -12% to +12%. The injection volume can be changed in fine gradations.
- 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.

Standard:





Result





Lean: During Control the Injection Volume, the A/F sensor output voltage (AFS Voltage B1S1) is consistently more than 3.4 V, and the HO2 sensor output voltage (O2S) is consistently less than 0.4 V.

Rich: During the AFS Voltage B1S1 is consistently less than 3.1 V, and the O2S is consistently more than 0.55 V.

Lean/Rich: During Control the Injection Volume of the Active Test, the output voltage of the HO2 sensor alternates correctly.

HINT
Refer to "Data List / Active Test" [AFS Voltage B1S1 and O2S B1S2] Data List / Active List.

B -- REPLACE AIR FUEL RATIO SENSOR
A -- Continue to next step.

6. CHECK INTAKE SYSTEM

(a) Check the intake system for vacuum leak Intake System.

OK:

No leak from intake system.

NG -- REPAIR OR REPLACE INTAKE SYSTEM Intake System
OK -- Continue to next step.

7. CHECK FOR EXHAUST GAS LEAK

(a) Check the exhaust gas leak.

OK:

No gas leak.

NG -- REPAIR OR REPLACE EXHAUST SYSTEM
OK -- Continue to next step.

8. CHECK FUEL PRESSURE

(a) Check the fuel pressure Fuel System.

NG -- CHECK FUEL LINE
OK -- Continue to next step.

9. INSPECT FUEL INJECTOR

(a) Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) Testing and Inspection.

NG -- REPLACE FUEL INJECTOR Removal
OK -- Continue to next step.

10. REPLACE AIR FUEL RATIO SENSOR

(a) Replace the air fuel ratio sensor Removal.

NEXT -- Continue to next step.

11. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear DTCs Reading and Clearing Diagnostic Trouble Codes.

(e) Turn the ignition switch off and wait for at least 30 seconds.

(f) Turn the ignition switch to ON.

(g) Turn the Techstream on.

(h) Start the engine and warm it up.

(i) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(j) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

(k) Input the DTC: P2195 or P2196.

(l) Check the DTC judgment.

Result





B -- END
A -- Continue to next step.

12. REPLACE ECM

(a) Replace the ECM Removal.

NEXT -- Continue to next step.

13. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear DTCs Reading and Clearing Diagnostic Trouble Codes.

(e) Turn the ignition switch off and wait for at least 30 seconds.

(f) Turn the ignition switch to ON.

(g) Turn the Techstream on.

(h) Start the engine and warm it up.

(i) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(j) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

(k) Input the DTC: P2195 or P2196.

(l) Check the DTC judgment.

Result





NEXT -- END

14. REPLACE AIR FUEL RATIO SENSOR

(a) Replace the air fuel ratio sensor Removal.

NEXT -- Continue to next step.

15. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear DTCs Reading and Clearing Diagnostic Trouble Codes.

(e) Turn the ignition switch off and wait for at least 30 seconds.

(f) Turn the ignition switch to ON.

(g) Turn the Techstream on.

(h) Start the engine and warm it up.

(i) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(j) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

(k) Input the DTC: P2195 or P2196.

(l) Check the DTC judgment.

Result





B -- REPLACE ECM Removal

A -- END

16. CHECK FUEL LINE

(a) Check the fuel lines for leaks or blockage.

NG -- REPAIR OR REPLACE FUEL LINE

OK -- REPLACE FUEL PUMP