P2195
2AZ-FXE ENGINE CONTROL: SFI SYSTEM: P2195,P2196: Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1)
P2196 - Oxygen (A/F) Sensor Signal Stuck Rich (Bank 1 Sensor 1)
DESCRIPTION
HINT
- Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.
- Bank 1 sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.
The air fuel ratio sensor generates a voltage* that corresponds to the actual air fuel ratio. This sensor voltage is used to provide the hybrid vehicle control ECU with feedback so that it can control the air fuel ratio. The hybrid vehicle control ECU determines the deviation from the stoichiometric air fuel ratio level, and regulates the fuel injection time. If the air fuel ratio sensor malfunctions, the hybrid vehicle control ECU is unable to control the air fuel ratio accurately.
The air fuel ratio sensor is the planar type and is integrated with the heater, which heats the solid electrolyte (zirconia element). This heater is controlled by the hybrid vehicle control ECU. 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, therefore the sensor activation is accelerated.
In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxide (NOx) components in the exhaust gas, a three-way catalytic converter is used. For the most efficient use of the three-way catalytic converter, the air fuel ratio must be precisely controlled so that it is always close to the stoichiometric level.
*: Value changes inside the hybrid vehicle control ECU. Since the air fuel ratio sensor is a current output element, the current is converted into a voltage inside the hybrid vehicle control ECU. Any measurements taken at the air fuel ratio sensor or hybrid vehicle control ECU connectors will show a constant voltage.
HINT
- When any of these DTCs are set, check the air fuel ratio sensor voltage output by entering the following menus 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 hybrid vehicle control ECU regulates the voltages at the A1A+ and A1A- terminals of the hybrid vehicle control ECU to a constant level. Therefore, the air fuel ratio sensor voltage output cannot be confirmed without using the Techstream.
- If an air fuel ratio sensor malfunction is detected, the hybrid vehicle control ECU 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 hybrid vehicle control ECU determines that there is a malfunction in the air fuel ratio sensor. The hybrid vehicle control ECU 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 hybrid vehicle control ECU 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 air fuel ratio sensor current, and a lean air fuel mixture causes a high air fuel ratio sensor current. Therefore, the sensor output becomes low during acceleration, and it becomes high during deceleration with the throttle valve fully closed. The hybrid vehicle control ECU monitors the air fuel ratio sensor current during fuel-cut and detects any abnormal current values.
If the air fuel ratio sensor output is 3.6 mA or higher for more than 3 seconds of cumulative time, the hybrid vehicle control ECU interprets this as a malfunction in the air fuel ratio sensor and stores DTC P2195 (stuck on high side). If the air fuel ratio sensor output is below 1.0 mA for more than 3 seconds of cumulative time, the hybrid vehicle control ECU stores DTC P2196 (stuck on low side).
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.
WIRING DIAGRAM
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.
- Connect the Techstream to the DLC3.
- Turn the power switch on (IG).
- Turn the Techstream on.
- Clear the DTCs DTC Check / Clear.
- Turn the power switch off and wait for at least 30 seconds.
- Turn the power switch on (IG) and turn the Techstream on.
- Put the engine in inspection mode Component Tests and General Diagnostics.
- Start the engine, and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher [A].
- On the Techstream, enter the following menus to check the fuel-cut status: Powertrain / Engine and ECT / Data List / All Data / Idle Fuel Cut.
- Drive the vehicle at between 47 and 75 mph (75 and 120 km/h) for at least 10 minutes [B].
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
- Move the shift lever in B [C].
- Accelerate the vehicle to 47 mph (75 km/h) or more by depressing the accelerator pedal for at least 10 seconds [D].
- Soon after performing step [D] above, release the accelerator pedal for at least 8 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 1800 rpm or more (fuel injection returns at 1500 rpm).
- Allow the vehicle to decelerate until the vehicle speed decreases to less than 6 mph (10 km/h).
- Repeat steps [C] through [E] above at least 3 times in one driving cycle.
- Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
- Read the pending DTC [F].
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 and ECT / Utility / All Readiness.
- Input the DTC: P2195 or P2196.
- 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].
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 sensor, heated oxygen 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.
- Connect the Techstream to the DLC3.
- Turn the power switch on (IG) and turn the Techstream on.
- Put the engine in inspection mode Component Tests and General Diagnostics.
- Start the engine.
- Turn the Techstream on.
- Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
- Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
- Perform the Active Test operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).
- Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2) 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 in the fuel injection volume.
NOTICE:
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.
- Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the voltage outputs of both the air fuel ratio and heated oxygen 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.
HINT
- Read freeze frame data using the Techstream. The hybrid vehicle control ECU records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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 air fuel ratio sensor voltage could be caused by a rich air fuel mixture. Check for conditions that would cause the engine to run rich.
- A high air fuel ratio 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 power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read the DTCs.
Result:
HINT
If any DTCs other than P2195 and P2196 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 AIR FUEL RATIO SENSOR)
YES -- DTC CAUSED BY RUNNING OUT OF FUEL
3. READ VALUE USING TECHSTREAM (TEST VALUE OF AIR FUEL RATIO SENSOR)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs DTC Check / Clear.
(e) Put the engine in inspection mode Component Tests and General Diagnostics.
(f) Drive the vehicle referring to the Confirmation Driving Pattern.
(g) Enter the following menus: Powertrain / Engine and ECT / Monitor / O2 Sensor / Status 2.
(h) Check that the Status 2 of O2 Sensor is Complete.
If the status is still Incomplete, perform the drive pattern increasing the vehicle speed and moving the shift lever to B to decelerate the vehicle.
(j) Enter the following menus: Powertrain / Engine and ECT / Monitor / O2 Sensor / Details / RANGE B1 S1.
(k) 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.
4. READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF AIR FUEL RATIO SENSOR)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG) and turn the Techstream on.
(c) Put the engine in inspection mode Component Tests and General Diagnostics.
(d) Start the engine.
(e) Warm up the air fuel ratio sensor at an engine speed of 2500 rpm for 90 seconds.
(f) Enter the following menus: Powertrain / Engine and ECT / Data List / AFS Voltage B1S1 and Engine Speed, then press the Record button.
(g) Check the air fuel ratio sensor voltage 3 times, when the engine is in each of the following conditions:
(1) While idling (check for at least 30 seconds) (Step "A").
(2) At an engine speed of approximately 2500 rpm (without any sudden changes in engine speed) (Step "B").
(3) The engine speed is raised to 2500 rpm and then the accelerator pedal is quickly released so that the throttle valve is fully closed (Step "C").
Standard Voltage:
HINT
For more information, see the diagrams below.
HINT
- If the output voltage of the air fuel ratio sensor remains at approximately 3.3 V (see Malfunction Condition diagram) under any conditions, including those above, the air fuel ratio sensor may have an open circuit. (This will also happen if the air fuel ratio sensor heater has an open circuit.)
- If the output voltage of the air fuel ratio sensor remains at either approximately 3.8 V or higher, or below 2.8 V (see Malfunction Condition diagram) under any conditions, including those above, the air fuel ratio sensor may have a short circuit.
- The hybrid vehicle control ECU stops fuel injection (fuel cut) during engine deceleration. This causes a lean condition and results in a momentary increase in the air fuel ratio sensor output voltage.
- When the vehicle is being driven:
- The output voltage of the air fuel ratio 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 air fuel ratio sensor is functioning normally.
- The air fuel ratio sensor is a current output element; therefore, the current is converted into a voltage inside the hybrid vehicle control ECU. Measuring the voltage at the connectors of the air fuel ratio sensor or hybrid vehicle control ECU will show a constant voltage result.
NG -- INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
OK -- Continue to next step.
5. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs.
(e) Put the engine in inspection mode Component Tests and General Diagnostics.
(f) Drive the vehicle referring to the Confirmation Driving Pattern.
NEXT -- Continue to next step.
6. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)
(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 / Pending.
(e) Read the Pending DTCs.
Result:
B -- CHECK FOR INTERMITTENT PROBLEMS
A -- Continue to next step.
7. REPLACE AIR FUEL RATIO SENSOR
(a) Replace the air fuel ratio sensor Removal.
NEXT -- Continue to next step.
8. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs.
(e) Put the engine in inspection mode Component Tests and General Diagnostics.
(f) Drive the vehicle referring to the Confirmation Driving Pattern.
NEXT -- Continue to next step.
9. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)
(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 / Pending.
(e) Read the Pending DTCs.
Result:
B -- END
A -- REPLACE HYBRID VEHICLE CONTROL ECU Removal
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 (AIR FUEL RATIO SENSOR - HYBRID VEHICLE CONTROL ECU)
(a) Disconnect the air fuel ratio sensor connector.
(b) Disconnect the hybrid vehicle control ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Standard Resistance (Check for Short):
(d) Reconnect the air fuel ratio sensor connector.
(e) Reconnect the hybrid vehicle control ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
12. CHECK INTAKE SYSTEM
(a) Check the intake system for vacuum leaks Testing and Inspection.
OK:
No leaks in the intake system.
NG -- REPAIR OR REPLACE INTAKE SYSTEM
OK -- Continue to next step.
13. CHECK FUEL PRESSURE
(a) Check the fuel pressure Testing and Inspection.
NG -- REPAIR OR REPLACE FUEL SYSTEM
OK -- Continue to next step.
14. INSPECT FUEL INJECTOR ASSEMBLY
(a) Check the fuel injector assembly injection (whether fuel volume is high or low, and whether injection pattern is poor) Testing and Inspection.
NG -- REPLACE FUEL INJECTOR ASSEMBLY Removal
OK -- Continue to next step.
15. REPLACE AIR FUEL RATIO SENSOR
(a) Replace the air fuel ratio sensor Removal.
NEXT -- Continue to next step.
16. PERFORM CONFIRMATION DRIVING PATTERN
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs.
(e) Put the engine in inspection mode Component Tests and General Diagnostics.
(f) Drive the vehicle referring to the Confirmation Driving Pattern.
NEXT -- Continue to next step.
17. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)
(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 / Pending.
(e) Read the Pending DTCs.
Result:
B -- END
A -- REPLACE HYBRID VEHICLE CONTROL ECU Removal