P2197
2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2195: Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1)
DTC P2195 - Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1)
DTC P2196 - Oxygen (A/F) Sensor Signal Stuck Rich (Bank 1 Sensor 1)
DTC P2197 - Oxygen (A/F) Sensor Signal Stuck Lean (Bank 2 Sensor 1)
DTC P2198 - Oxygen (A/F) Sensor Signal Stuck Rich (Bank 2 Sensor 1)
DESCRIPTION
HINT:
- Although the DTC titles refer to the "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 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, and 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.
HINT: *: Value changes inside the ECM. Since the A/F sensor is the current output element, the current is converted to 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 output voltage by entering the following menus on the Techstream: Powertrain / Engine and ECT / Data List / A/F Control System / AFS B1 S1 or AFS B2 S1.
- 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 output voltage cannot be confirmed without using the Techstream.
- If an 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 output voltage indicates rich or lean for a certain period of time, the ECM determines that 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) for 10 seconds, despite the HO2 sensor output voltage being less than 0.6 V, the ECM sets DTC P2196. Alternatively, if the A/F sensor output voltage is more than 3.8 V (very lean condition) for 15 seconds, despite the HO2 sensor output voltage being 0.15 V or more, DTC P2195 is set.
- 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 high during acceleration, and the sensor becomes low during deceleration.
The ECM monitors the air-fuel ratio sensor current during fuel-cut and detects unusual current value. If the cumulative time sensor output exceeds 3 seconds, the ECM interprets a malfunction in the air-fuel ratio sensor and sets a DTC.
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 and 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 (Rich 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.
- Performing this confirmation driving pattern will activate the Heated Oxygen (HO2) sensor monitor. (The catalyst monitor is performed simultaneously.) This is very useful for verifying the completion of a repair.
NOTE: 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 ignition switch ON.
3 Turn the tester ON.
4 Clear DTCs DTC Check / Clear.
5 Warm-up the engine until the engine coolant temperature is 75°C (167°F) or more [A].
6 Drive the vehicle at between 60 km/h and 120 km/h (40 mph and 75 mph) for at least 10 minutes or more [B].
7 Drive the vehicle 60 km/h (40 mph) or more and decelerate the vehicle for 5 seconds or more. Perform this 3 times [C].
8 Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
9 Input DTCs: P2195, P2196, P2197 and P2198.
10 Check that Monitor is NORMAL. If Monitor is INCOMPLETE, perform the drive pattern adding the vehicle speed and using the second gear 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.
1 Connect the Techstream to the DLC3.
2 Start the engine and turn the tester ON.
3 Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
4 On the Techstream, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
5 Perform the Control the Injection Volume for A/F Sensor operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
6 Monitor the output voltages of the A/F and HO2 sensors (AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2) displayed on the tester.
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.
Standard Voltage:
NOTE: 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 on the tester: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2.
HINT:
- Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
- 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, 2197 OR P2198)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON.
(c) Turn the tester ON
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read the DTCs.
Result:
HINT: If any DTCs other than P2195, P2196, P2197 or P2198 are output, troubleshoot those DTCs first.
B -- GO TO DTC CHART
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 ignition switch ON and turn the tester ON.
(c) Clear the DTCs DTC Check / Clear.
(d) Allow the vehicle to drive in accordance with the drive pattern described in the CONFIRMATION DRIVING PATTERN.
(e) Enter the following menus: Powertrain / Engine and ECT / Monitor / O2 Sensor.
(f) Check the status of O2 Sensor is Complete.
If the status is still Incomplete, drive the vehicle according to the driving pattern again.
HINT:
- Complete indicates that the component is functioning normally.
- Incomplete indicates that the component is malfunctioning.
(g) Enter the following menus: Powertrain / Engine and ECT / Monitor / O2 Sensor / Details / RANGE B1 S1 or RANGE B2 S1.
(h) 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) Start the engine.
(c) Turn the tester ON.
(d) Warm up the Air Fuel Ratio (A/F) sensor at an engine speed of 2500 rpm for 90 seconds.
(e) On the tester, enter the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / Snapshot / AFS B1 S1 or AFS B2 S1 and Engine Speed.
(f) Check the A/F sensor voltage three times, when the engine is in each of the following conditions:
Operation Steps
Standard voltage:
HINT:
- For more information, see the diagrams below.
- If the output voltage of the A/F sensor remains at approximately 0.66 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 0.76 V or more, or 0.56 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 10 mph (16 km/h) 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 0.56 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) Read the DTCs using the Techstream.
(b) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Result:
B -- CONFIRM WHETHER VEHICLE HAS RUN OUT OF FUEL IN PAST
A -- Continue to next step.
6. REPLACE AIR FUEL RATIO SENSOR
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) Read the DTCs using the Techstream.
(b) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
Result:
B -- REPLACE ECM AND PERFORM CONFIRMATION DRIVING PATTERN
A -- Continue to next step.
9. CONFIRM WHETHER VEHICLE HAS RUN OUT OF FUEL IN PAST
NO -- CHECK FOR INTERMITTENT PROBLEMS
YES -- DTC CAUSED BY RUNNING OUT OF FUEL
10. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
(a) Disconnect the A41 or A42 A/F sensor connector.
(b) Measure the resistance of the A/F sensor connector.
Standard resistance:
(c) Reconnect the A/F sensor connector.
NG -- REPLACE AIR FUEL RATIO SENSOR
OK -- Continue to next step.
11. INSPECT A/F HEATER RELAY
(a) Remove the A/F HEATER relay from the engine room R/B.
(b) Measure the resistance of the A/F HEATER relay.
Standard resistance:
(c) Reinstall the A/F HEATER relay.
NG -- REPLACE A/F HEATER RELAY
OK -- Continue to next step.
12. CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)
(a) Disconnect the A41 or A42 A/F sensor connector.
(b) Turn the ignition switch ON.
(c) Measure the voltage between the +B terminal of the A/F sensor connector and body ground.
Standard voltage:
(d) Turn the ignition switch OFF.
(e) Disconnect the E6 ECM connector.
(f) Check the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(g) Reconnect the A/F sensor connector.
(h) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
13. CHECK AIR INDUCTION SYSTEM
(a) Check the air induction system for vacuum leakage.
OK:
No leakage from air induction system.
NG -- REPAIR OR REPLACE AIR INDUCTION SYSTEM
OK -- Continue to next step.
14. CHECK FUEL PRESSURE
(a) Check the fuel pressure Testing and Inspection.
NG -- REPAIR OR REPLACE FUEL SYSTEM
OK -- Continue to next step.
15. INSPECT FUEL INJECTOR ASSEMBLY
(a) Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor).
NG -- REPLACE FUEL INJECTOR ASSEMBLY
OK -- Continue to next step.
16. REPLACE AIR FUEL RATIO SENSOR
NEXT -- Continue to next step.
17. PERFORM CONFIRMATION DRIVING PATTERN
NEXT -- Continue to next step.
18. CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)
(a) Read the DTCs using the Techstream.
(b) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
Result:
B -- REPLACE ECM AND PERFORM CONFIRMATION DRIVING PATTERN
A -- Continue to next step.
19. CONFIRM WHETHER VEHICLE HAS RUN OUT OF FUEL IN PAST
NO -- CHECK FOR INTERMITTENT PROBLEMS
YES -- DTC CAUSED BY RUNNING OUT OF FUEL
20. REPLACE AIR FUEL RATIO SENSOR
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 ignition switch ON and turn the tester ON.
(c) Read the DTCs using the Techstream.
(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
Result:
B -- REPLACE ECM
A -- END