P2196
1UR-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 the No. 1 cylinder*.
*: The No. 1 cylinder is the cylinder which is farthest from the transmission.
- Bank 2 refers to the bank that does not include the No. 1 cylinder.
- Sensor 1 refers to the sensor closest to the engine assembly.
- Sensor 2 refers to the sensor farthest away from the engine assembly.
- When any of these DTCs are set, check the A/F sensor voltage output by entering the following menus: Powertrain / Engine / Data List / A/F Control System / AFS Voltage B1S1 or AFS Voltage B2S1.
- 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 more to less than 0.21 V for 5 seconds, the ECM sets DTC P2196 or P2198. Alternatively, if the A/F sensor voltage output is more than 3.8 V (very lean condition) and HO2 sensor output voltage rises from less than 0.21 V to 0.59 V or more 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 (Lean side malfunction P2195, P2197):
Sensor voltage detection monitor (Rich side malfunction P2196, P2198):
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.
CONFIRMATION DRIVING PATTERN
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 engine switch on (IG).
3. Turn the Techstream on.
4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) Reading and Clearing Diagnostic Trouble Codes.
5. Turn the engine switch off and wait for at least 30 seconds.
6. Turn the engine switch on (IG) and turn the Techstream on.
7. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher [A].
8. On the Techstream, enter the following menus to check the fuel-cut status: Powertrain / Engine / Data List / Idle Fuel Cut.
9. Drive the vehicle at a speed between 37 and 75 mph (60 and 120 km/h) 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 40 mph (64 km/h) 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 5 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 6 mph (10 km/h).
14. Repeat steps [C] through [E] above at least 3 times in one driving cycle.
15. Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
16. Read the pending DTCs [F].
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 / Utility / All Readiness.
18. Input the DTC: P2195, P2196, P2197 or P2198.
19. Check the DTC judgment result.
HINT
- 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 the test result is INCOMPLETE or UNKNOWN and 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 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) Start the engine and turn the Techstream on.
(c) Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
(d) On the Techstream, enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F sensor.
(e) Perform the Active Test operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume.)
(f) 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 / 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
- 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 engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine / Trouble Codes.
(e) Read the DTCs.
Result
HINT
If any DTCs relating to the A/F sensor (DTCs for the A/F sensor heater or A/F sensor admittance) are output, troubleshoot those DTCs first.
B -- GO TO DTC CHART 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 A/F SENSOR)
YES -- Continue to next step.
3. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(e) Turn the engine switch off and wait for 30 seconds.
(f) Turn the engine switch on (IG) and then the Techstream on.
(g) Start the engine and warm it up.
(h) Drive the vehicle in accordance with the drive pattern described in the Confirmation Driving Pattern.
(i) Enter the following menus: Powertrain / Engine / Utility / All Readiness.
(j) Check the DTC judgment result.
Result
B -- READ VALUE USING TECHSTREAM (TEST VALUE OF A/F SENSOR)
A -- DTC CAUSED BY RUNNING OUT OF FUEL
4. READ VALUE USING TECHSTREAM (TEST VALUE OF A/F SENSOR)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(e) Drive the vehicle in accordance with the drive pattern described in the Confirmation Driving Pattern.
(f) Enter the following menus: Powertrain / Engine / Monitor / Current Monitor / O2 Sensor.
(g) Check that the status of O2 Sensor is Complete.
If the status is still Incomplete, perform the drive pattern increasing the vehicle speed and using the second gear to decelerate the vehicle.
(h) Enter the following menus: Powertrain / Engine / Monitor / Current Monitor / O2 Sensor / Details / RANGE B1S1 or RANGE B2S1.
(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.
5. READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF A/F SENSOR)
(a) Connect the Techstream to the DLC3.
(b) Start the engine.
(c) Turn the Techstream on.
(d) Warm up the air fuel ratio sensor at an engine speed of 2500 rpm for 90 seconds.
(e) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume / AFS Voltage B1S1, AFS Voltage B2S1, O2S B1S2 and O2S B2S2.
(f) Perform the Control the Injection Volume operation with the engine idling.
(g) Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2 or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.
HINT
- Change the fuel injection volume within the range of -12.0% to +12.0%. 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.
Result
Lean: During the Control the Injection Volume Active Test, the air fuel ratio sensor output voltage (AFS Voltage) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2S) is consistently below 0.4 V.
Rich: During the Control the Injection Volume Active Test, the AFS Voltage is consistently below 3.1 V, and the O2S is consistently higher than 0.55 V.
Lean/Rich: During the Control the Injection Volume Active Test, the output voltage of the heated oxygen sensor alternates correctly.
HINT
Refer to "Data List / Active Test" [AFS Voltage B1S1, AFS Voltage B2S1, O2S B1S2 and O2S B2S2] Data List / Active Test.
C -- CHECK FOR INTERMITTENT PROBLEMS Check For Intermittent Problems
B -- REPLACE AIR FUEL RATIO SENSOR
A -- Continue to next step.
6. CHECK AIR INDUCTION SYSTEM
(a) Check the air induction system for vacuum leak.
OK:
No leak from air induction system.
NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK -- Continue to next step.
7. INSPECT EXHAUST GAS LEAK
NG -- REPAIR OR REPLACE EXHAUST GAS LEAK
OK -- Continue to next step.
8. CHECK FUEL PRESSURE (FOR LOW PRESSURE SIDE)
(a) Check the fuel pressure Fuel System.
NG -- REPAIR OR REPLACE FUEL SYSTEM (LOW PRESSURE SIDE)
OK -- Continue to next step.
9. 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.
10. READ VALUE USING TECHSTREAM (FUEL PRESS)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the Techstream on.
(c) Start the engine.
(d) Enter the following menus: Powertrain / Engine / Data List / All Data / Fuel Press.
(e) While revving the engine, check that the fuel pressure fluctuates.
Standard:
Idling
3000 to 5000 kPa
2000 rpm (No load)
7000 to 9000 kPa
HINT
The A/C switch and all accessory switches should be OFF, and the transmission gear selector 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.
11. 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.
12. REPLACE AIR FUEL RATIO SENSOR
(a) Replace the air fuel ratio sensor.
HINT
- for 2WD Removal.
- for AWD Removal.
NEXT -- Continue to next step.
13. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(e) Turn the engine switch off and wait for 30 seconds.
(f) Turn the engine switch on (IG) and then the Techstream on.
(g) Start the engine and warm it up.
(h) Drive the vehicle in accordance with the drive pattern described in the Confirmation Driving Pattern.
NEXT -- Continue to next step.
14. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine / Utility / All Readiness.
(e) Check the DTC judgment result.
Result
B -- REPLACE ECM Removal
A -- END