P2198

2UR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2195-P2198: Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1)


DESCRIPTION

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.

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. The heat generated by the heater is conducted to the solid electrolyte through the alumina, 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
- DTCs P2195 and P2196 indicate malfunctions related to bank 1 A/F sensor circuit.
- DTCs P2197 and P2198 indicate malfunctions related to bank 2 A/F sensor circuit.
- Bank 1 refers to the bank that includes No. 1 cylinder.
- Bank 2 refers to the bank that includes No. 2 cylinder.
- When any of these DTCs are set, check the A/F sensor voltage output by entering the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / AFS Voltage B1S1 or AFS Voltage B1S1.
- Short-term fuel trim values can also be read using the Techstream.
- The ECM regulates the voltages at the A1A+, A2A+, A1A- and A2A- 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 A/F sensor voltage output indicates rich or lean for a certain period of time, the ECM determines that there is a malfunction in the A/F sensor. The ECM illuminates the MIL and sets a DTC.

Example:

If the A/F sensor voltage output is less than 2.8 V (very rich condition) and HO2 sensor output voltage falls from 0.59 V or higher to below 0.21 V for 5 seconds, the ECM sets DTC P2196 or P2198. Alternatively, if the A/F sensor voltage output is higher than 3.8 V (very lean condition) and HO2 sensor output voltage rises from below 0.21 V to 0.59 V or higher for 5 seconds, DTC P2195 or P2197 is set.

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 3.6 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 or P2197 (high-side stuck). If the A/F sensor output is less than 0.78 mA for more than 3 seconds of cumulative time, the ECM sets DTC P2196 or P2198 (low-side stuck).





MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

ALL





Sensor voltage detection monitor:





Sensor current detection monitor (P2195, P2196, P2197, P2198):





TYPICAL MALFUNCTION THRESHOLDS

Sensor voltage detection monitor (Lean side malfunction P2195, P2197):





Sensor voltage detection monitor (Rich side malfunction P2196, P2198):





Sensor current detection monitor (High side malfunction P2195, P2197):





Sensor current detection monitor (Low side malfunction P2196, P2198):





MONITOR RESULT

Refer to CHECKING MONITOR STATUS Mode 6 Data.

WIRING DIAGRAM





CONFIRMATION DRIVING PATTERN

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

NOTICE:
This test will not be completed if the vehicle is driven under absolutely constant speed conditions such as with cruise control activated.





1. Connect the Techstream to the DLC3.

2. Turn the power switch on (READY).

3. Warm-up the engine until the engine coolant temperature is 75°C (167°F) or more [A].

4. Drive the vehicle at between 70 km/h and 120 km/h (45 mph and 75 mph) for at least 10 minutes or more [B].

5. Stop the vehicle.

6. Repeat the following drive pattern three times [C]:

- Accelerate the vehicle to 80 km/h (50 mph) for 10 seconds or more.

- Move the shift lever to S3 range, and decelerate the vehicle for 4 seconds or more.

7. Turn the Techstream ON.

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

9. Input DTCs: P2195, P2196, P2197 and P2198.

10. Check that DTC MONITOR is NORMAL. If DTC MONITOR is INCOMPLETE, perform the drive pattern by increasing the vehicle speed and using the S2 range to decelerate the vehicle.

INSPECTION PROCEDURE

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

(a) Connect the Techstream to the DLC3.
(b) Put the engine in inspection mode Inspection Mode Procedure.
(c) Turn the Techstream ON.
(d) Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
(e) On the Techstream, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F sensor.
(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 or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.

HINT
- The Control the Injection Volume for A/F sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.
- 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 for A/F sensor 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 for A/F Sensor / A/F Control System / AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2.

HINT
- When viewed from the rear of the engine assembly, Bank 1 is on the left side and Bank 2 is on the right side.
- 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, P2196, P2197 OR P2198)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(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, P2196, P2197 or P2198 are output, troubleshoot those DTCs first.

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

2. READ VALUE USING TECHSTREAM (TEST VALUE OF A/F SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG) and turn the Techstream ON.

(c) Clear DTCs DTC Check / Clear.

(d) Turn the power switch on (READY).

(e) Allow the vehicle to drive in accordance with the drive pattern described in the "CONFIRMATION DRIVING PATTERN".

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

(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 / O2 Sensor / Details / RANGE B1S1 or RANGE B2S1 / Details.

(i) Check the test value of the A/F sensor output current during fuel-cut.

Result





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

3. READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF A/F SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Put the engine in inspection mode Inspection Mode Procedure.

(c) Turn the Techstream ON.

(d) Warm up the engine.

(e) Enter the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / Snapshot / AFS Voltage B1S1 or AFS Voltage B1S1 and Engine Speed.

(f) Check the A/F sensor voltage three times, when the engine is in each of the following conditions:

(1) While idling (check for at least 30 seconds)

(2) Fully depress the accelerator pedal and run the engine at 2500 rpm.

(3) Accelerator pedal released.

Standard:





HINT
For more information, see the diagrams below.





HINT
- If the output voltage of the A/F sensor remains at approximately 3.3 V (see Malfunction Condition diagram) under any conditions, including those above, the A/F sensor may have an open circuit. (This will also happen if the A/F sensor heater has an open circuit.)
- If the output voltage of the A/F sensor remains at either approximately 3.8 V or higher, or 2.8 V or less (see Malfunction Condition diagram) under any conditions, including those above, the A/F sensor may have a short circuit.
- The ECM stops fuel injection (fuel cut) during engine deceleration. This causes a lean condition and results in a momentary increase in the A/F sensor output voltage.
- The ECM must establish a closed throttle valve position learning value to perform fuel cut. If the battery terminal has been reconnected, the vehicle must be driven over 16 km/h (10 mph) to allow the ECM to learn the closed throttle valve position.
- When the vehicle is driven:
The output voltage of the A/F sensor may be below 2.8 V during fuel enrichment. For the vehicle, this translates to a sudden increase in speed with the accelerator pedal fully depressed when trying to overtake another vehicle. The A/F sensor is functioning normally.
- The A/F sensor is a current output element; therefore, the current is converted into a voltage inside the ECM. Measuring the voltage at the connectors of the A/F sensor or ECM will show a constant voltage result.

NG -- INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
OK -- Continue to next step.

4. PERFORM CONFIRMATION DRIVING PATTERN

NEXT -- Continue to next step.

5. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG) and turn the Techstream ON.

(c) Enter the following menus: Powertrain / Engine and ECT / Data List / Trouble Codes / Pending.

(d) Read DTCs.

Result





B -- CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST
A -- Continue to next step.

6. REPLACE AIR FUEL RATIO SENSOR

(a) Replace the air fuel ratio sensor Removal.

NEXT -- Continue to next step.

7. PERFORM CONFIRMATION DRIVING PATTERN

NEXT -- Continue to next step.

8. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG) and turn the Techstream ON.

(c) Enter the following menus: Powertrain / Engine and ECT / Data List / Trouble Codes / Pending.

(d) Read DTCs.

Result





B -- REPLACE ECM AND PERFORM CONFIRMATION DRIVING PATTERN Removal

A -- END

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

NO -- CHECK FOR INTERMITTENT PROBLEMS Check For Intermittent Problems

YES -- DTC CAUSED BY RUNNING OUT OF FUEL

10. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE) P0031

NG -- REPLACE AIR FUEL RATIO SENSOR Removal
OK -- Continue to next step.

11. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM) P0171

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

12. CHECK AIR INDUCTION SYSTEM

(a) Check the air induction system for vacuum leakage Testing and Inspection.

OK:

No leakage from air induction system.

NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM Removal
OK -- Continue to next step.

13. CHECK FUEL PRESSURE

(a) Check the fuel pressure Testing and Inspection.

NG -- REPAIR OR REPLACE FUEL SYSTEM (LOW PRESSURE SIDE)
OK -- Continue to next step.

14. INSPECT FUEL INJECTOR FOR PORT INJECTION

(a) Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) Fuel Injector (for Port Injection).

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

15. READ VALUE USING TECHSTREAM (FUEL PRESS)

(a) Connect the Techstream to the DLC3.

(b) Put the engine in inspection mode Inspection Mode Procedure.

(c) Turn the Techstream ON.

(d) Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Fuel Press.

(e) While revving the engine, check that the fuel pressure fluctuates.

Standard:

Idling
3500 to 4500 kPa

2500 rpm (No load)
7000 to 9000 kPa

HINT
The A/C switch and all accessory switches should be OFF, the shift lever should be in the N or P position, and the engine should be fully warmed up.

NG -- REPAIR OR REPLACE FUEL SYSTEM (HIGH PRESSURE SIDE)
OK -- Continue to next step.

16. INSPECT FUEL INJECTOR FOR DIRECT INJECTION

(a) Inspect the fuel injector for direct injection Fuel Injector (for Direct Injection).

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

17. REPLACE AIR FUEL RATIO SENSOR

(a) Replace the air fuel ratio sensor Removal.

NEXT -- Continue to next step.

18. PERFORM CONFIRMATION DRIVING PATTERN

NEXT -- Continue to next step.

19. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG) and turn the Techstream ON.

(c) Enter the following menus: Powertrain / Engine and ECT /Trouble Codes / Pending.

(d) Read DTCs.

Result





B -- REPLACE ECM AND PERFORM CONFIRMATION DRIVING PATTERN Removal

A -- END

20. REPLACE AIR FUEL RATIO SENSOR

(a) Replace the air fuel ratio sensor Removal.

NEXT -- Continue to next step.

21. PERFORM CONFIRMATION DRIVING PATTERN

NEXT -- Continue to next step.

22. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG) and turn the Techstream ON.

(c) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

(d) Read DTCs.

Result





B -- REPLACE ECM Removal

A -- END