P2195
3UR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2195-P2198: Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1)
CAUTION / NOTICE / HINT
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 air-fuel ratio 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, 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 either of these DTCs is set, check the A/F sensor output voltage by entering the following menus: Powertrain / Engine and ECT / 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+ and A1A- or A2A+ and A2A- terminals of the ECM to a constant level. Therefore, the A/F sensor output voltage cannot be confirmed without using the Techstream.
* If the A/F sensor is malfunctioning, the ECM sets the DTC P2195, P2196, P2197 or P2198.
MONITOR DESCRIPTION
Sensor voltage detection monitor
Under the air-fuel ratio feedback control, if the A/F sensor output voltage 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 output voltage is less than 2.8 V (very rich condition) for 5 seconds, despite the rear HO2 sensor output voltage being less than 0.59 V, the ECM sets DTC P2196 or P2198. Alternatively, if the A/F sensor output voltage is more than 3.8 V (very lean condition) for 5 seconds despite the rear HO2 sensor output voltage being 0.21 V or more, 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 1.4 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:
TYPICAL MALFUNCTION THRESHOLDS
Sensor voltage detection monitor (Lean side malfunction P2195 and P2197):
Sensor voltage detection monitor (Rich side malfunction P2196 and P2198):
Sensor current detection monitor (High side malfunction P2195 and P2197):
Sensor current detection monitor (Rich side malfunction P2196 and P2198):
CONFIRMATION DRIVING PATTERN
This confirmation driving pattern is used in the "PERFORM CONFIRMATION DRIVING PATTERN" procedure of the following diagnostic troubleshooting procedure.
1. Connect 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 Techstream, select the following menu items to check the fuel-cut status: Powertrain / Engine and ECT / Data List / Idle Fuel Cut.
9. Drive the vehicle at between 60 km/h (38 mph) and 120 km/h (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].
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 2,500 rpm or more (fuel injection returns at 1,000 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, 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].
20. If the 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.
MONITOR RESULT
Refer to CHECKING MONITOR STATUS Mode 6 Data.
WIRING DIAGRAM
INSPECTION PROCEDURE
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.
* DTC P2A00 may be set when the air-fuel ratio is stuck rich or lean.
* 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.
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) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
- (e) Perform the Control the Injection Volume for A/F Sensor 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%.
* The sensors react in accordance with increases and decreases in the fuel injection volume.
Standard:
NOTICE:
The A/F sensor has an output delay of a few seconds and the HO2 sensor (for Sensor 2) output 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 on the Techstream: 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.
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 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 relating to the air fuel ratio sensor (DTCs for the air fuel ratio sensor heater or air fuel ratio 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 ignition switch to ON.
(c) Turn the Techstream on.
(d) Clear the 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 and turn the Techstream on.
(g) Start the engine and warm it up.
(h) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
(i) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
(j) Input the DTC: P2195, P2196, P2197 or P2198.
(k) 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 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 drive 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 B1 S1 or RANGE B2 S1.
(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. 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 and ECT / Active Test / Control the Injection Volume.
(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% 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.
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 List.
B -- REPLACE AIR FUEL RATIO SENSOR
A -- Continue to next step.
6. CHECK AIR INDUCTION SYSTEM
(a) Check the air induction system for vacuum leaks Intake System.
OK:
No leaks in air induction system.
NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK -- Continue to next step.
7. CHECK EXHAUST GAS LEAK
(a) Check for exhaust gas leaks from the exhaust manifold assembly and exhaust pipes.
OK:
No gas leaks.
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 ASSEMBLY
(a) Check the fuel injector (whether fuel volume is high or low, and whether injector pattern is poor) Testing and Inspection.
NG -- REPLACE FUEL INJECTOR ASSEMBLY 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. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Clear the 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 and turn the Techstream on.
(g) Start the engine and warm it up.
(h) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
(i) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
(j) Input the DTC: P2195, P2196, P2197 or P2198.
(k) Check the DTC judgment result.
Result
B -- END
A -- Continue to next step.
12. REPLACE ECM
(a) Replace the ECM Removal.
NEXT -- Continue to next step.
13. CONFIRM CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Clear the DTC 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 and turn the Techstream on.
(g) Start the engine and warm it up.
(h) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
(i) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
(j) Input the DTC: P2195, P2196, P2197 or P2198.
(k) Check the DTC judgment result.
Result
NEXT -- END
14. REPLACE AIR FUEL RATIO SENSOR
(a) Replace the air fuel ratio sensor Removal.
NEXT -- Continue to next step.
15. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Clear the 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 and turn the Techstream on.
(g) Start the engine and warm it up.
(h) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
(i) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
(j) Input the DTC: P2195, P2196, P2197 or P2198.
(k) Check the DTC judgment result.
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 ASSEMBLY Removal