| DTC Code | DTC Name |
|---|---|
| P21951D | O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 1 Circuit Current Out of Range |
| P219523 | O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 1 Signal Stuck Low |
| P21961D | O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 1 Circuit Current Out of Range |
| P219624 | O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 1 Signal Stuck High |
DESCRIPTION
Tech Tips
Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.
The air fuel ratio 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, 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 a planar type and 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), current flows to the heater to heat the sensor, in order to facilitate accurate oxygen concentration detection. In addition, the sensor and heater portions are a narrow type. The heat generated by the heater is conducted to the solid electrolyte through alumina, therefore 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 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 air fuel ratio.
*: 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. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Memory | Note |
|---|---|---|---|---|---|---|
| P21951D | O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 1 Circuit Current Out of Range | While the fuel-cut operation is performed (during vehicle deceleration), the air fuel ratio sensor current is 2.2 mA or higher for 3 seconds or more (2 trip detection logic). |
|
Comes on | DTC stored | SAE Code: P2195 |
| P219523 | O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 1 Signal Stuck Low | Both of the following conditions are met for 5 seconds or more (2 trip detection logic):
|
|
Comes on | DTC stored | SAE Code: P2195 |
| P21961D | O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 1 Circuit Current Out of Range | While the fuel-cut operation is performed (during vehicle deceleration), the air fuel ratio sensor current is less than 0.7 mA for 3 seconds or more (2 trip detection logic). |
|
Comes on | DTC stored | SAE Code: P2196 |
| P219624 | O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 1 Signal Stuck High | Both of the following conditions are met for 5 seconds or more (2 trip detection logic):
|
|
Comes on | DTC stored | SAE Code: P2196 |
Tech Tips
When any of these DTCs are stored, check the air fuel ratio sensor output voltage by entering the following menus on the GTS: Powertrain / Engine / Data List / A/F (O2) Sensor Voltage B1S1.
Short-term fuel trim values can also be read using the GTS.
The ECM regulates the voltages at terminals A1A+ and A1A- of the ECM to a constant level. Therefore, the air fuel ratio sensor output voltage cannot be confirmed without using the GTS.
If an air fuel ratio sensor malfunction is detected, the ECM will store a DTC.
MONITOR DESCRIPTION
Under air fuel ratio feedback control, If the air fuel ratio sensor output voltage is less than 2.8 V (very rich condition) for 5 seconds despite the heated oxygen sensor output voltage being less than 0.7 V, the ECM stores DTC P219624. Alternatively, if the air fuel ratio sensor output voltage is higher than 3.8 V (very lean condition) for 5 seconds despite the heated oxygen sensor output voltage being 0.21 V or higher, DTC P219523 is stored.
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 ECM monitors the air fuel ratio sensor current during fuel-cut and detects any abnormal current values.
If the air fuel ratio sensor output is 2.2 mA or higher for 3 seconds or more of cumulative time, the ECM interprets this as a malfunction of the air fuel ratio sensor and stores DTC P21951D (stuck on high side). If the air fuel ratio sensor output is less than 0.7 mA for 3 seconds or more of cumulative time, the ECM stores DTC P21961D (stuck on low side).
MONITOR STRATEGY
| Required Sensors/Components (Main) | Air fuel ratio sensor |
| Required Sensors/Components (Related) | Heated oxygen sensor |
| Frequency of Operation | Continuous: Sensor voltage detection monitor Once per driving cycle: Sensor current detection monitor |
| Duration | 3 seconds: Sensor current detection monitor 5 seconds: Sensor voltage detection monitor |
TYPICAL ENABLING CONDITIONS
| Time after engine start | 30 seconds or more |
| Air fuel ratio sensor status | Activated |
| Fuel system status | Closed-loop |
| Air fuel ratio imbalance of clogged EGR runner fail | Not set |
| Auxiliary battery voltage | 11 V or higher |
| Engine coolant temperature | 75°C (167°F) or higher |
| Atmospheric pressure | 76 kPa(abs) [11 psi(abs)] or higher |
| Air fuel ratio sensor status | Activated |
| Continuous time of fuel-cut | 3 seconds or more, and less than 10 seconds |
| Air fuel ratio imbalance of clogged EGR runner fail | Not set |
TYPICAL MALFUNCTION THRESHOLDS
| Heated oxygen sensor voltage | 0.21 V or higher |
| Air fuel ratio sensor voltage | Higher than 3.8 V |
| Heated oxygen sensor voltage | Less than 0.7 V |
| Air fuel ratio sensor voltage | Less than 2.8 V |
| Duration of following condition | 3 seconds or more |
| Air fuel ratio sensor current | 2.2 mA or higher |
| Duration of following condition | 3 seconds or more |
| Air fuel ratio sensor current | Less than 0.7 mA |
CONFIRMATION DRIVING PATTERN
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off and wait for at least 30 seconds.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in Inspection Mode (Maintenance Mode).
Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher [A].
Press the EV/HV mode selection switch to select HV mode.
With the engine running, drive the vehicle at a speed between 75 and 100 km/h (47 and 62 mph) for at least 10 minutes [B].
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
Tech Tips
If the engine stops, further depress the accelerator pedal to restart the engine.
With shift state B selected [C] and the engine running, accelerate the vehicle to 75 km/h (47 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.
Tech Tips
If the engine stops, further depress the accelerator pedal to restart the engine.
Soon after performing step [D] above, release the accelerator pedal for at least 5 seconds without depressing the brake pedal in order to execute fuel-cut control [E].
Allow the vehicle to decelerate until the vehicle speed is 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 / Trouble Codes [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 / Utility / All Readiness.
Input the DTC: P21951D, P219523, P21961D or P219624.
Check the DTC judgment result.
| GTS Display | Description |
|---|---|
| NORMAL |
|
| ABNORMAL |
|
| INCOMPLETE |
|
| N/A |
|
Tech Tips
If the judgment result is NORMAL, the system is normal.
If the judgment result is ABNORMAL, the system is malfunctioning.
If the judgment result is INCOMPLETE or N/A, perform steps [B] through [F] again.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
Note
Inspect the fuses for circuits related to this system before performing the following procedure.
Tech Tips
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.
Sensor 1 refers to the sensor closest to the engine assembly.
Sensor 2 refers to the sensor farthest away from the engine assembly.
Read freeze frame data using the GTS. The ECM 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.
PROCEDURE
CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P21951D, P219523, P21961D OR P219624)
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine / Trouble Codes.
Read the DTCs.
| Result | |||||||
|---|---|---|---|---|---|---|---|
|
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.
| B |
|
GO TO DTC CHART Click here |
| A |
|
CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST
Has the vehicle run out of fuel in the past?
| Result | |||
|---|---|---|---|
|
| NO |
|
CLEAR DTC Click here |
| YES |
|
CLEAR DTC
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the power switch off and wait for at least 30 seconds.
| Result | ||
|---|---|---|
|
| NEXT |
|
CHECK WHETHER DTC OUTPUT RECURS (DTC P21951D, P219523, P21961D OR P219624)
Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
| Tester Display |
|---|
| All Readiness |
Input the DTC: P21951D, P219523, P21961D or P219624.
Check the DTC judgment result.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| A |
|
DTC CAUSED BY RUNNING OUT OF FUEL |
| B |
|
CLEAR DTC
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the power switch off and wait for at least 30 seconds.
| Result | ||
|---|---|---|
|
| NEXT |
|
READ VALUE USING GTS (A/F (O2) SENSOR CURRENT B1S1)
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in Inspection Mode (Maintenance Mode).
| Tester Display |
|---|
| Inspection Mode |
Start the engine.
Enter the following menus: Powertrain / Engine / Data List / A/F (O2) Sensor Current B1S1.
| Tester Display |
|---|
| A/F (O2) Sensor Current B1S1 |
Check the test value of the air fuel ratio sensor output current during fuel-cut, referring to the Driving Pattern Detail for [C] through [E] in Confirmation Driving Pattern.
Tech Tips
To measure the air fuel ratio sensor current precisely, perform the fuel-cut operation as long as possible.
If it is difficult to measure the air fuel ratio sensor current, use the snapshot function of the GTS.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| B |
|
REPLACE AIR FUEL RATIO SENSOR Click here |
| A |
|
PERFORM ACTIVE TEST USING GTS (CONTROL THE INJECTION VOLUME FOR A/F SENSOR)
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in Inspection Mode (Maintenance Mode).
| Tester Display |
|---|
| Inspection Mode |
Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.
Idle the engine for 5 minutes or more with park (P) selected.
Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / Data List / A/F (O2) Sensor Voltage B1S1 and O2 Sensor Voltage B1S2.
| Active Test Display |
|---|
| Control the Injection Volume for A/F Sensor |
| Data List Display |
|---|
| A/F (O2) Sensor Voltage B1S1 |
| O2 Sensor Voltage B1S2 |
Change the fuel injection volume using the GTS, and monitor the output voltage of the air fuel ratio sensor (A/F (O2) Sensor Voltage B1S1) and heated oxygen sensor (O2 Sensor Voltage B1S2) displayed on the GTS.
Tech Tips
The Active Test "Control the Injection Volume for A/F Sensor" can be used to lower the fuel injection volume by 12.5% or increase the injection volume by 12.5%.
The air fuel ratio sensor is displayed as A/F (O2) Sensor Voltage B1S1, and the heated oxygen sensor is displayed as O2 Sensor Voltage B1S2 on the GTS.
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.
If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.
| GTS Display (Sensor) | Injection Volume | Status | Voltage |
|---|---|---|---|
| A/F (O2) Sensor Voltage B1S1 (Air fuel ratio) |
12.5% | Rich | Below 3.1 V |
| -12.5% | Lean | Higher than 3.4 V | |
| O2 Sensor Voltage B1S2 (Heated oxygen) |
12.5% | Rich | Higher than 0.55 V |
| -12.5% | Lean | Below 0.4 V |
| Result | ||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Lean: While performing the Active Test "Control the Injection Volume for A/F Sensor", the air fuel ratio sensor output voltage (A/F (O2) Sensor Voltage B1S1) is consistently higher than 3.4 V, and the heated oxygen sensor output voltage (O2 Sensor Voltage B1S2) is consistently below 0.4 V.
Rich: While performing the Active Test "Control the Injection Volume for A/F Sensor", the air fuel ratio sensor output voltage (A/F (O2) Sensor Voltage B1S1) is consistently below 3.1 V, and the heated oxygen sensor output voltage (O2 Sensor Voltage B1S2) is consistently higher than 0.55 V.
Lean/Rich: While performing the Active Test "Control the Injection Volume for A/F Sensor", the output voltage of the fuel ratio sensor (A/F (O2) Sensor Voltage B1S1) or heated oxygen sensor (O2 Sensor Voltage B1S2) alternates correctly.
Tech Tips
Refer to "Data List / Active Test" [A/F (O2) Sensor Voltage B1S1 and O2 Sensor Voltage B1S2].
| B |
|
GO TO STEP 17 Click here |
| C |
|
PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION) Click here |
| A |
|
CHECK INTAKE SYSTEM
Check the intake system for vacuum leaks.
| OK |
|---|
| No leaks from the intake system. |
Tech Tips
Perform "Inspection After Repair" after repairing or replacing the intake system.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE INTAKE SYSTEM |
| OK |
|
CHECK FOR EXHAUST GAS LEAK
Check for exhaust gas leaks.
| OK |
|---|
| No gas leaks in exhaust system. |
Tech Tips
Perform "Inspection After Repair" after repairing or replacing the exhaust system.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE EXHAUST SYSTEM |
| OK |
|
PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION)
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in Inspection Mode (Maintenance Mode).
| Tester Display |
|---|
| Inspection Mode |
Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.
Tech Tips
The A/C switch and all accessories should be off.
Enter the following menus: Powertrain / Engine / Active Test / Control the EGR Step Position / Data List / Intake Manifold Absolute Pressure and Engine Independent.
| Active Test Display |
|---|
| Control the EGR Step Position |
| Data List Display |
|---|
| Intake Manifold Absolute Pressure |
| Engine Independent |
Confirm that the value of Data List item Engine Independent is "Operate" then check the value of Intake Manifold Absolute Pressure while performing the Active Test.
Note
Do not leave the EGR valve open for 10 seconds or more during the Active Test.
Be sure to return the EGR valve to step 0 when the Active Test is completed.
Do not open the EGR valve 30 steps or more during the Active Test.
| OK |
|---|
| The value of Intake Manifold Absolute Pressure changes in response to the EGR step position when the value of Engine Independent is "Operate". |
| Standard | ||||||||
|---|---|---|---|---|---|---|---|---|
|
||||||||
Tech Tips
If the value of Data List item Engine Independent is "Not Opr" when the engine is idling, charge control is being performed. Perform the Active Test after charge control is complete ("Operate" is displayed).
While performing the Active Test, if the increase in the value of Intake Manifold Absolute Pressure is small, the EGR valve assembly may be malfunctioning.
Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of Intake Manifold Absolute Pressure may occur while performing the Active Test. However, the amount that the value of Intake Manifold Absolute Pressure increases will be smaller than normal.
| Result | |||
|---|---|---|---|
|
| OK |
|
GO TO STEP 12 Click here |
| NG |
|
INSPECT EGR VALVE ASSEMBLY
Remove the EGR valve assembly.
Check if the EGR valve is stuck open.
| OK |
|---|
| EGR valve is tightly closed. |
| Result | |||
|---|---|---|---|
|
| NG |
|
REPLACE EGR VALVE ASSEMBLY Click here |
| OK |
|
CHECK FUEL PRESSURE
Check the fuel pressure.
| Result | |||
|---|---|---|---|
|
| NG |
|
INSPECT FUEL PUMP Click here |
| OK |
|
INSPECT FUEL INJECTOR ASSEMBLY
Inspect the fuel injector assembly (whether fuel volume is high or low, and whether injection pattern is poor).
| Result | |||
|---|---|---|---|
|
| OK |
|
GO TO STEP 17 Click here |
| NG |
|
REPLACE FUEL INJECTOR ASSEMBLY Click here |
INSPECT FUEL PUMP
Inspect the fuel pump.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPAIR OR REPLACE FUEL LINE |
| NG |
|
REPLACE FUEL PUMP Click here |
PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION)
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Put the engine in Inspection Mode (Maintenance Mode).
| Tester Display |
|---|
| Inspection Mode |
Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.
Tech Tips
The A/C switch and all accessories should be off.
Enter the following menus: Powertrain / Engine / Active Test / Control the EGR Step Position / Data List / Intake Manifold Absolute Pressure and Engine Independent.
| Active Test Display |
|---|
| Control the EGR Step Position |
| Data List Display |
|---|
| Intake Manifold Absolute Pressure |
| Engine Independent |
Confirm that the value of Data List item Engine Independent is "Operate" then check the value of Intake Manifold Absolute Pressure while performing the Active Test.
Note
Do not leave the EGR valve open for 10 seconds or more during the Active Test.
Be sure to return the EGR valve to step 0 when the Active Test is completed.
Do not open the EGR valve 30 steps or more during the Active Test.
| OK |
|---|
| The value of Intake Manifold Absolute Pressure changes in response to the EGR step position when the value of Engine Independent is "Operate". |
| Standard | ||||||||
|---|---|---|---|---|---|---|---|---|
|
||||||||
Tech Tips
If the value of Data List item Engine Independent is "Not Opr" when the engine is idling, charge control is being performed. Check the engine speed after charge control is complete ("Operate" is displayed).
While performing the Active Test, if the increase in the value of Intake Manifold Absolute Pressure is small, the EGR valve assembly may be malfunctioning.
Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of Intake Manifold Absolute Pressure may occur while performing the Active Test. However, the amount that the value of Intake Manifold Absolute Pressure increases will be smaller than normal.
| Result | |||
|---|---|---|---|
|
| OK |
|
GO TO STEP 17 Click here |
| NG |
|
INSPECT EGR VALVE ASSEMBLY
Remove the EGR valve assembly.
Check if the EGR valve is stuck open.
| OK |
|---|
| EGR valve is tightly closed. |
| Result | |||
|---|---|---|---|
|
| NG |
|
REPLACE EGR VALVE ASSEMBLY Click here |
| OK |
|
REPLACE AIR FUEL RATIO SENSOR
Replace the air fuel ratio sensor.
| Result | ||
|---|---|---|
|
| NEXT |
|
CLEAR DTC
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the power switch off and wait for at least 30 seconds.
| Result | ||
|---|---|---|
|
| NEXT |
|
CHECK WHETHER DTC OUTPUT RECURS (DTC P21951D, P219523, P21961D OR P219624)
Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
| Tester Display |
|---|
| All Readiness |
Input the DTC: P21951D, P219523, P21961D or P219624.
Check the DTC judgment result.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| A |
|
END |
| B |
|
REPLACE ECM Click here |