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

Tech Tips

Although the DTC titles say heated oxygen sensor, these DTCs relate to the air fuel ratio sensor.
Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) 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 ECM with feedback so that it can control the air fuel ratio. The ECM determines the deviation from the stoichiometric air fuel ratio 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 a 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 through 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, thereby accelerating the sensor activation.

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.

*: The value changes inside the ECM. Since the air fuel ratio sensor is a current output element, the current is converted into 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) are met for 2 seconds or more (2 trip detection logic): (a) The air fuel ratio sensor voltage is higher than 3.8 V. (b) The heated oxygen sensor voltage is 0.15 V or higher.	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 fuel ratio sensor heater circuits No. 1 integration relay (A/F) Air induction system circuits Fuel pressure Fuel injector assembly ECM
P2195 P2197	While the fuel-cut operation is performed (during vehicle deceleration), the air fuel ratio sensor current is 3.6 mA or higher for 3 seconds (2 trip detection logic).	Air fuel ratio sensor ECM
P2196 P2198	Conditions (a) and (b) are met for 2 seconds or more (2 trip detection logic): (a) The air fuel ratio sensor voltage is below 2.8 V. (b) The heated oxygen sensor voltage is below 0.6 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 fuel ratio sensor heater circuits Air induction system No. 1 integration relay (A/F) Fuel pressure Fuel injector assembly ECM
P2196 P2198	While the fuel-cut operation is performed (during vehicle deceleration), the air fuel ratio sensor current is below than 1.4 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.
Bank 1 refers to the bank that includes cylinder No. 1.
Bank 2 refers to the bank that includes cylinder No. 2.
When any of these DTCs are stored, check the air fuel ratio sensor voltage output by entering the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / AFS Voltage B1S1 or AFS Voltage B2S1.
The short-term fuel trim values can also be read using the intelligent tester.
The ECM maintains the voltages at the A1A+, A2A+, A1A- and A2A- terminals of the ECM at 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 stores a DTC.

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

CAUTION:

Strictly observe posted speed limits, traffic laws and road conditions when performing these driving patterns.

Tech Tips

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

(a) Connect the intelligent tester to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the intelligent tester on.
(d) Clear DTCs Click here.
(e) Start the engine and warm it up until the ECT reaches 75°C (167°F) or higher.
(f) Enter the following menus to check the fuel-cut status: Powertrain / Engine and ECT / Data List / All Data / Idle Fuel Cut.
(g) Drive the vehicle at between 60 km/h (38 mph) and 120 km/h (75 mph) for at least 10 minutes.
(h) Shift the transmission to 2nd gear.
(i) Drive the vehicle at the proper vehicle speed to perform fuel-cut operation (refer to the following hint).
Tech Tips

Fuel-cut is performed when the following conditions are met:
- The accelerator pedal is fully released.
- The engine speed is 2500 rpm or more (fuel injection returns at 1000 rpm).
(j) Accelerate the vehicle to 64 km/h (40 mph) or more by depressing the accelerator pedal for at least 10 seconds.
(k) Soon after performing step (j) above, release the accelerator pedal for at least 4 seconds without depressing the brake pedal in order to execute fuel-cut control.
(l) Allow the vehicle to decelerate until the vehicle speed decreases to less than 10 km/h (6 mph).
(m) Repeat steps (h) through (k) above at least 3 times in one driving cycle.

Tech Tips

Completion of O2S (A/F) Monitor is required to change the value in the Data List.

INSPECTION PROCEDURE

Tech Tips

Malfunctioning areas can be identified by performing the Control the Injection Volume for air fuel ratio sensor function provided in the Active Test. The Control the Injection Volume for air fuel ratio 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 air fuel ratio sensor operation using the intelligent tester.

Connect the intelligent tester to the DLC3.
Start the engine and turn the intelligent tester on.
Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
On the intelligent tester, 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, or AFS Voltage B2S1 and O2S B2S2) displayed on the intelligent tester.

Tech Tips

The Control the Injection Volume for air fuel ratio sensor operation lowers the fuel injection volume by 12.5% or increases the injection volume by 12.5%.
Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

Tester Display (Sensor)	Injection Volume	Status	Voltage
AFS Voltage B1S1 or AFS Voltage B2S1 (Air fuel ratio sensor)	+12.5%	Rich	Below 3.1 V
AFS Voltage B1S1 or AFS Voltage B2S1 (Air fuel ratio sensor)	-12.5%	Lean	Higher than 3.4 V
O2S B1S2 or O2S B2S2 (Heated oxygen sensor)	+12.5%	Rich	Higher than 0.55 V
O2S B1S2 or O2S B2S2 (Heated oxygen sensor)	-12.5%	Lean	Below 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 injector assembly Fuel pressure Gas leakage from exhaust system (air fuel ratio extremely rich or lean)

Following the Control the Injection Volume for air fuel ratio 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 or AFS Voltage B2S1 and O2S B2S2.

Tech Tips

Read freeze frame data using the intelligent tester. 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 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

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

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the intelligent tester on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read DTCs.

Result
Result	Proceed to
P2195, P2196, P2197 or P2198	A
P2195, P2196, P2197 or P2198 and other DTCs	B

Tech Tips

If any DTCs other than P2195, P2196, P2197 or P2198 are output, troubleshoot those DTCs first.

GO TO DTC CHART Click here

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

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the intelligent tester on.
Clear DTCs Click here.
Drive the vehicle in accordance with the driving pattern described in the 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
Result	Proceed to
Within normal range (1.4 mA or higher, and below 3.6 mA)	A
Outside normal range (Below 1.4 mA, or 3.6 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 intelligent 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 / Data List / A/F Control System / Snapshot / AFS Voltage B1S1 or AFS Voltage B2S1 and Engine Speed.

Check the air fuel ratio sensor voltage three times, once in each of the following conditions:

Engine idling (check for at least 30 seconds)
Engine running at an engine speed of approximately 2500 rpm (without any sudden changes in engine speed)

Engine speed raised to 4000 rpm and then accelerator pedal quickly released so that the throttle valve is fully closed

Standard

Condition

Air Fuel Ratio Sensor Voltage Variation

Reference

(1) and (2)

Changes at approximately 3.3 V

Between 3.1 V and 3.5 V

(3)

Increases to 3.8 V or higher

This occurs during engine deceleration

(during fuel-cut)

Tech Tips

For more information, see the diagrams below.

Tech Tips

If the output voltage of the air fuel ratio sensor remains at approximately 3.3 V (see "Malfunctioning" 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 2.8 V or less (see "Malfunctioning" diagram) under any conditions, including those above, the air fuel ratio 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 air fuel ratio sensor output voltage.
The ECM must establish a closed throttle valve position learned value to perform fuel cut. If the battery cable has been disconnected and reconnected, the vehicle must be driven over 16 km/h (10 mph) to allow the ECM to learn the closed throttle valve position.
When the vehicle is 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 ECM. Measuring the voltage at the connectors of the air fuel ratio sensor or ECM will show a constant voltage.

INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE) Click here

PERFORM CONFIRMATION DRIVING PATTERN

NEXT

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the intelligent tester on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

Read the DTCs.

Result
Result	Proceed to
P2195, P2196, P2197 or P2198	A
No output	B

CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST Click here

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

NEXT

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the intelligent tester on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

Read DTCs.

Result
Result	Proceed to
No output	A
P2195, P2196, P2197 or P2198	B

REPLACE ECM AND PERFORM CONFIRMATION DRIVING PATTERN

CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST

NO
CHECK FOR INTERMITTENT PROBLEMS Click here

YES

DTC CAUSED BY RUNNING OUT OF FUEL
INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
1. Inspect the air fuel ratio sensor Click here.
NG
REPLACE AIR FUEL RATIO SENSOR Click here

OK
INSPECT NO. 1 INTEGRATION RELAY (A/F)
1. Inspect the No. 1 integration relay (A/F) Click here.
NG
REPLACE NO. 1 INTEGRATION RELAY (A/F)

OK

CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

Disconnect the air fuel ratio sensor connector.
Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open)

Tester Connection	Condition	Specified Condition
C25-1 (HA1A) - C37-17 (HA1A)	Always	Below 1 Ω
C26-1 (HA2A) - C37-19 (HA2A)	Always	Below 1 Ω

Standard Resistance (Check for Short)

Tester Connection	Condition	Specified Condition
C25-1 (HA1A) or C37-17 (HA1A) - Body ground	Always	10 kΩ or higher
C26-1 (HA2A) or C37-19 (HA2A) - Body ground	Always	10 kΩ or higher

Reconnect the air fuel ratio sensor connector.
Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

OK
CHECK FUEL PRESSURE
1. Check the fuel pressure Click here.
NG
REPAIR OR REPLACE FUEL SYSTEM

OK
INSPECT FUEL INJECTOR ASSEMBLY
1. Check the injector injection (whether fuel volume is large or small, 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
PERFORM CONFIRMATION DRIVING PATTERN

NEXT

OK
No leakage in air induction system.

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the intelligent tester on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

Read DTCs.

Result
Result	Proceed to
No output	A
P2195, P2196, P2197 or P2198	B

REPLACE ECM AND PERFORM CONFIRMATION DRIVING PATTERN

CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST

NO
CHECK FOR INTERMITTENT PROBLEMS Click here

YES

DTC CAUSED BY RUNNING OUT OF FUEL
REPLACE AIR FUEL RATIO SENSOR
1. Replace the air fuel ratio sensor Click here.
NEXT
PERFORM CONFIRMATION DRIVING PATTERN

NEXT

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195, P2196, P2197 OR P2198)

Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON and turn the intelligent tester on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

Read DTCs.

Result
Display (DTC Output)	Proceed to
No output	A
P2195, P2196, P2197 or P2198 (air fuel ratio sensor pending DTCs)	B

REPLACE ECM Click here

END