SFI SYSTEM, Diagnostic DTC:P2195, P2196, P2197, P2198

DTC Code	DTC Name
P2195	Oxygen (A/F) Sensor Signal Stuck Lean (Bank 1 Sensor 1)
P2196	Oxygen (A/F) Sensor Signal Stuck Rich (Bank 1 Sensor 1)
P2197	Oxygen (A/F) Sensor Signal Stuck Lean (Bank 2 Sensor 1)
P2198	Oxygen (A/F) Sensor Signal Stuck Rich (Bank 2 Sensor 1)

DESCRIPTION

The air fuel ratio 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 air fuel ratio sensor malfunctions, the ECM 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 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. In addition, the sensor and heater portions are narrower than the conventional type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, therefore the sensor activation is accelerated.

A three-way catalytic converter is used in order to convert the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxides (NOx) into less harmful substances. To allow the three-way catalytic converter to function effectively, it is necessary to keep the air fuel ratio of the engine near the stoichiometric air fuel ratio.

*: Value changes inside the ECM. Since the air fuel ratio sensor is the current output element, a current is converted to a voltage inside the ECM. Any measurements taken at the air fuel ratio sensor or ECM connectors will show a constant voltage.

DTC No.	DTC Detection Condition	Trouble Area
P2195 P2197	Conditions (a) and (b) continue for 5 seconds or more (2 trip detection logic): (a) Air fuel ratio sensor voltage is more than 3.8 V (b) Heated oxygen sensor voltage is 0.21 V or more	Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) Air fuel ratio sensor (bank 1, 2 sensor 1) heater Air induction system Fuel pressure Fuel injector assembly ECM
P2195 P2197	While fuel-cut operation is performed (during vehicle deceleration), air fuel ratio sensor current is 2.2 mA or more for 3 seconds (2 trip detection logic)	Air fuel ratio sensor ECM
P2196 P2198	Conditions (a) and (b) continue for 5 seconds or more (2 trip detection logic): (a) Air fuel ratio sensor voltage is less than 2.8 V (b) Heated oxygen sensor voltage is less than 0.59 V	Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) Air fuel ratio sensor (bank 1, 2 sensor 1) heater Air induction system Fuel pressure Fuel injector assembly ECM
P2196 P2198	While fuel-cut operation is performed (during vehicle deceleration), air fuel ratio sensor current is less than 0.8 mA for 3 seconds (2 trip detection logic)	Air fuel ratio sensor ECM

Tech Tips

DTCs P2195 and P2196 indicate malfunctions related to the bank 1 air fuel ratio sensor circuit.
DTCs P2197 and P2198 indicate malfunctions related to the bank 2 air fuel ratio sensor circuit.
When any of these DTCs are set, check the air fuel ratio sensor voltage output by selecting the following menu items on the intelligent tester: Powertrain / Engine and ECT / Data List / All Data / AFS Voltage B1S1 or AFS Voltage B2S1.
Short-term fuel trim values can also be read using the intelligent tester.
The ECM regulates the voltages at the A1A+, A2A+, A1A- and A2A- terminals of the ECM to a constant level. Therefore, the air fuel ratio sensor voltage output cannot be confirmed without using the intelligent tester.
If an air fuel ratio sensor malfunction is detected, the ECM sets a DTC.

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

This confirmation driving pattern is used in the "Perform Confirmation Driving Pattern" procedure of the following diagnostic troubleshooting procedure.

Connect the intelligent tester to the DLC3.
Turn the ignition switch on (IG).
Turn the tester on.
Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch on (IG) and turn the tester on.
Start the engine and warm it up until the ECT reaches 75°C (167°F) or higher [A].
On the intelligent tester, enter the following menus to check the fuel-cut status: Powertrain / Engine and ECT / Data List / Idle Fuel Cut.
Drive the vehicle at a speed between 60 and 100 km/h (38 and 63 mph) for at least 10 minutes [B].

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.
Shift the transmission to 2nd gear [C].
Accelerate the vehicle to 60 km/h (38 mph) 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.
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].
Tech Tips

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).
Allow the vehicle to decelerate until the vehicle speed decreases to less than 10 km/h (6 mph).
Repeat steps [C] through [E] above at least 3 times in one driving cycle.
Enter the following menus: Powertrain / Engine and ECT / DTC [F].
Read the pending DTCs.
Tech Tips
- 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, P2196, P2197 or P2198.

Check the DTC judgment result.

Tester Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
UNKNOWN	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

Tech Tips

If the judgment result shows NORMAL, the system is normal.
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.

INSPECTION PROCEDURE

Note

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tech Tips

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 tester.

Connect the intelligent tester to the DLC3.
Start the engine and turn the tester 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 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).

Monitor the voltage outputs 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 tester.

Tech Tips

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.

Standard voltage

Tester Display	Injection Volumes	Status	Voltages
AFS Voltage B1S1 or AFS Voltage B2S1 (Air fuel ratio)	+25%	Rich	Less than 3.1 V
AFS Voltage B1S1 or AFS Voltage B2S1 (Air fuel ratio)	-12.5%	Lean	More than 3.4 V
O2S B1S2 or O2S B2S2 (Heated oxygen)	+25%	Rich	More than 0.55 V
O2S B1S2 or O2S B2S2 (Heated oxygen)	-12.5%	Lean	Less than 0.4 V

Note

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.

Case	Air Fuel Ratio Sensor (Sensor 1) Output Voltage	Heated Oxygen Sensor (Sensor 2) Output Voltage	Main Suspected Trouble Area
1			-
2			Air fuel ratio sensor Air fuel ratio sensor heater Air fuel ratio sensor circuit
3			Heated oxygen sensor Heated oxygen sensor heater Heated oxygen sensor circuit
4			Fuel pressure Gas leakage from exhaust system (Air fuel ratio extremely lean or rich)

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 on the tester: Control the Injection Volume for A/F Sensor / All Data / AFS Voltage B1S1 or AFS Voltage B2S1 and O2S B1S2 or O2S B2S2. Then press the graph button on the Data List view.
Tech Tips
- Read freeze frame data using the intelligent tester. 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 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.
- 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.

PROCEDURE

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P2195, P2196, P2197 OR P2198)

Connect the intelligent tester to the DLC3.
Turn the ignition switch on (IG).
Turn the tester on.
Enter the following menus: Powertrain / Engine and ECT / DTC.

Read the DTCs.

Result

Display (DTC Output)	Proceed to
P2195, P2196, P2197 or P2198 is output	A
P2195, P2196, P2197 or P2198 and P0136, P0137, P0138, P0156, P0157 or P0158 are output	A
P2195, P2196, P2197 or P2198 and other DTCs	B

Tech Tips

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.

GO TO DTC CHART Click here

CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST
1. Has the vehicle run out of fuel in the past?
NO
READ VALUE USING INTELLIGENT TESTER (TEST VALUE OF AIR FUEL RATIO SENSOR) Click here

YES

PERFORM CONFIRMATION DRIVING PATTERN

Connect the intelligent tester to the DLC3.
Turn the ignition switch on (IG).
Turn the tester on.
Clear the DTCs Click here.
Turn the ignition switch off.
Turn the ignition switch on (IG) and turn the tester on.
Start the engine and warm it up.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P2195, P2196, P2197 or P2198.

Check the DTC judgment result.

Result
Result	Proceed to
NORMAL (DTC is not output)	A
ABNORMAL (DTC P2195, P2196, P2197 or P2198 is output)	B

READ VALUE USING INTELLIGENT TESTER (TEST VALUE OF AIR FUEL RATIO SENSOR) Click here

DTC CAUSED BY RUNNING OUT OF FUEL

READ VALUE USING INTELLIGENT TESTER (TEST VALUE OF AIR FUEL RATIO SENSOR)

Connect the intelligent tester to the DLC3.
Turn the ignition switch on (IG) and turn the tester on.
Clear the DTCs Click here.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / AFS Current B1S1 and AFS Current B2S1.

Check the test value of the air fuel ratio sensor output current during fuel-cut.

Result

Test Value	Proceed to
Within normal range (0.8 mA or higher, and below 2.2 mA)	A
Outside normal range (below 0.8 mA, or 2.2 mA or higher)	B

REPLACE AIR FUEL RATIO SENSOR Click here

READ VALUE USING INTELLIGENT TESTER (OUTPUT VOLTAGE OF AIR FUEL RATIO SENSOR)

Connect the intelligent tester to the DLC3.
Start the engine.
Turn the tester on.
Warm up the air fuel ratio sensor at an engine speed of 2500 rpm for 90 seconds.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume.
Perform the Control the Injection Volume operation with the engine idling.

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 tester.

Tech Tips

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.

Tester Display (Sensor)	Injection Volume	Status	Voltage
AFS Voltage B1S1 or AFS Voltage B2S1 (Air fuel ratio)	+12.0%	Rich	Below 3.1 V
AFS Voltage B1S1 or AFS Voltage B2S1 (Air fuel ratio)	-12.0%	Lean	Higher than 3.4 V
O2S B1S2 or O2S B2S2 (Heated oxygen)	+12.0%	Rich	Higher than 0.55 V
O2S B1S2 or O2S B2S2 (Heated oxygen)	-12.0%	Lean	Below 0.4 V

Result
Status of AFS Voltage B1S1 or AFS Voltage B2S1	Status of O2S B1S2 or O2S B2S2	Air Fuel Ratio Condition and Air Fuel Ratio Sensor Condition	Misfire	Suspected Trouble Area	Proceed to
Lean	Lean	Actual air fuel ratio lean	May occur	PCV valve and hose PCV hose connections Fuel injector assembly blockage Gas leaks from exhaust system Intake system Fuel pressure Mass air flow meter sub-assembly Engine coolant temperature sensor	A
Rich	Rich	Actual air fuel ratio rich	-	Fuel injector assembly leakage or blockage Gas leaks from exhaust system Ignition system Fuel pressure Mass air flow meter sub-assembly Engine coolant temperature sensor	A
Lean	Lean/Rich	Air fuel ratio sensor malfunction	-	Air fuel ratio sensor	B
Rich	Lean/Rich	Air fuel ratio sensor malfunction	-	Air fuel ratio sensor	B
Lean/Rich	Lean/Rich	Normal	-	-	C

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.

Tech Tips

Refer to "Data List / Active Test" [AFS Voltage B1S1, AFS Voltage B2S1, O2S B1S2 and O2S B2S2] Click here.

REPLACE AIR FUEL RATIO SENSOR Click here

CHECK FOR INTERMITTENT PROBLEMS Click here

CHECK AIR INDUCTION SYSTEM
1. Check the air induction system for vacuum leakage.
  
  OK
  
  No leakage from air induction system.
NG
REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK
CHECK FOR EXHAUST GAS LEAK

Check for exhaust gas leaks.

OK

No gas leaks.

NG
REPAIR OR REPLACE EXHAUST SYSTEM

OK
CHECK FUEL PRESSURE
1. Check the fuel pressure Click here.
NG
CHECK FUEL LINE Click here

OK
INSPECT FUEL INJECTOR ASSEMBLY
1. Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) Click here.
NG
REPLACE FUEL INJECTOR ASSEMBLY Click here

OK
REPLACE AIR FUEL RATIO SENSOR
1. Replace the air fuel ratio sensor Click here.
NEXT

OK
No leakage from air induction system.

OK
No gas leaks.

PERFORM CONFIRMATION DRIVING PATTERN

Connect the intelligent tester to the DLC3.
Turn the ignition switch on (IG).
Turn the tester on.
Clear the DTCs Click here.
Turn the ignition switch off and wait for 30 seconds.
Turn the ignition switch on (IG) and turn the tester on.
Start the engine and warm it up.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P2195, P2196, P2197 or P2198.

Check the DTC judgment result.

Result
Result	Proceed to
ABNORMAL (DTC P2195, P2196, P2197 or P2198 is output)	A
NORMAL (DTC is not output)	B

END

REPLACE ECM
1. Replace the ECM Click here.
NEXT

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

Connect the intelligent tester to the DLC3.
Turn the ignition switch on (IG).
Turn the tester on.
Clear the DTC Click here.
Turn the ignition switch off and wait for 30 seconds.
Turn the ignition switch on (IG) and turn the tester on.
Start the engine and warm it up.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P2195, P2196, P2197 or P2198.

Check the DTC judgment result.

Result
Tester Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
UNKNOWN	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

END

REPLACE AIR FUEL RATIO SENSOR
1. Replace the air fuel ratio sensor Click here.
NEXT

PERFORM CONFIRMATION DRIVING PATTERN

Connect the intelligent tester to the DLC3.
Turn the ignition switch on (IG).
Turn the tester on.
Clear the DTCs Click here.
Turn the ignition switch off and wait for 30 seconds.
Turn the ignition switch on (IG) and turn the tester on.
Start the engine and warm it up.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P2195, P2196, P2197 or P2198.

Check the DTC judgment result.

Result
Result	Proceed to
NORMAL (DTC is not output)	A
ABNORMAL (DTC P2195, P2196, P2197 or P2198 is output)	B

REPLACE ECM Click here

END

CHECK FUEL LINE
1. Check the fuel lines for leaks or blockage.
NG
REPAIR OR REPLACE FUEL LINE

OK

REPLACE FUEL PUMP Click here