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 level, and regulates the fuel injection duration. 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 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 a narrow type. The heat generated by the heater is conducted to the solid electrolyte through the 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 level.
*: 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 0.47 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 voltage output 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 the A1A+ and A1A- terminals 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 0.68 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 more than 3 seconds or more of cumulative time, the ECM interprets this as a malfunction in the air fuel ratio sensor and stores DTC P21951D (stuck on high side). If the air fuel ratio sensor output is less than 0.47 mA for more than 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 |
Battery voltage | 11 V or higher |
Engine coolant temperature | 75°C (167°F) or higher |
Atmospheric pressure | 76 kPa(abs) [11.02 psi(abs)] or higher |
Air fuel ratio sensor status | Activated |
Continuous time of fuel-cut | 3 seconds or more, and less than 10 seconds |
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 0.69 V |
Air fuel ratio sensor voltage | Less than 2.8 V |
Air fuel ratio sensor current | 2.2 mA or higher |
Air fuel ratio sensor current | Less than 0.47 mA |
CONFIRMATION DRIVING PATTERN
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG) and turn the GTS on.
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher [A].
Drive the vehicle at a speed between 60 and 100 km/h (37 and 62 mph) for at least 10 minutes [B].
CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
With the shift lever in M [C], accelerate the vehicle to 60 km/h (37 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 5 seconds without depressing the brake pedal in order to execute fuel-cut control [E].
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 / 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 shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows 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 engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine / Trouble Codes.
Read the DTCs.
Result | |||||||
---|---|---|---|---|---|---|---|
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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 |
READ VALUE USING GTS (A/F (O2) SENSOR CURRENT B1S1) Click here |
YES |
CHECK WHETHER DTC OUTPUT RECURS (DTC P21951D, P219523, P21961D OR P219624)
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG) and turn the GTS 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 / 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 |
READ VALUE USING GTS (A/F (O2) SENSOR CURRENT B1S1)
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs.
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 | ||||||
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|
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 engine switch on (IG).
Turn the GTS on.
Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.
Warm up the air fuel ratio sensor at an engine speed of 2500 rpm for 90 seconds.
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 |
Perform the Control the Injection Volume for A/F Sensor operation with the engine idling.
Monitor the output voltages of the air fuel ratio and heated oxygen sensors (A/F (O2) Sensor Voltage B1S1 and O2 Sensor Voltage B1S2) displayed on the GTS.
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 12.5%.
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.
Standard | ||||||||||||||||||
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Result | |||||||||||||||||||||
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Lean: During the Control the Injection Volume for A/F Sensor of the Active Test, the air fuel ratio sensor output voltages (A/F (O2) Sensor Voltage B1S1) is consistently higher than 3.4 V, and the heated oxygen sensor output voltages (O2 Sensor Voltage B1S2) is consistently below 0.4 V.
Rich: During the Control the Injection Volume for A/F Sensor of the Active Test, the A/F (O2) Sensor Voltage B1S1 is consistently below 3.1 V, and the O2 Sensor Voltage B1S2 is consistently higher than 0.55 V.
Lean/Rich: During Control the Injection Volume for A/F Sensor of the Active Test, the output voltage of the air fuel ratio sensor or heated oxygen sensor 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 15 Click here |
A |
CHECK INTAKE SYSTEM
Check the intake system for vacuum leaks.
OK |
---|
No leaks in 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. |
Tech Tips
Perform "Inspection After Repair" after repairing or replacing the exhaust system.
Result | |||
---|---|---|---|
|
NG |
REPAIR OR REPLACE EXHAUST SYSTEM |
OK |
CHECK FUEL PRESSURE (FOR LOW PRESSURE SIDE)
Check the fuel pressure (for low pressure side).
Result | |||
---|---|---|---|
|
NG |
CHECK FUEL LINE Click here |
OK |
INSPECT PORT FUEL INJECTOR ASSEMBLY
Inspect the port fuel injector assembly (whether fuel volume is high or low, and whether injection pattern is poor).
Tech Tips
Perform "Inspection After Repair" after replacing the port fuel injector assembly.
Result | |||
---|---|---|---|
|
NG |
REPLACE PORT FUEL INJECTOR ASSEMBLY Click here |
OK |
READ VALUE USING GTS (FUEL PRESSURE (HIGH))
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Start the engine and warm it up.
Enter the following menus: Powertrain / Engine / Data List / Fuel Pressure (High).
Tester Display |
---|
Fuel Pressure (High) |
Read the values.
Standard |
---|
4000 to 8000 kPag (3000 rpm, engine warmed up, shift lever in P, A/C off). |
Result | |||
---|---|---|---|
|
NG |
REPAIR OR REPLACE FUEL SYSTEM (FOR HIGH PRESSURE SIDE) |
OK |
INSPECT DIRECT FUEL INJECTOR ASSEMBLY
Inspect the direct fuel injector assembly.
Tech Tips
Perform "Inspection After Repair" after replacing the direct fuel injector assembly.
Result | |||
---|---|---|---|
|
NG |
REPLACE DIRECT FUEL INJECTOR ASSEMBLY Click here |
OK |
REPLACE AIR FUEL RATIO SENSOR
Replace the air fuel ratio sensor.
Result | ||
---|---|---|
|
NEXT |
CHECK WHETHER DTC OUTPUT RECURS (DTC P21951D, P219523, P21961D OR P219624)
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG) and turn the GTS 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 / Utility / All Readiness.
Tester Display |
---|
All Readiness |
Input the DTC: P21951D, P219523, P21961D or P219624.
Check the DTC judgment result.
Result | ||||||
---|---|---|---|---|---|---|
|
A |
REPLACE ECM Click here |
B |
END |
CHECK FUEL LINE
Check the fuel lines for leaks or blockage.
Result | |||
---|---|---|---|
|
OK |
GO TO FUEL PUMP CONTROL CIRCUIT Click here |
NG |
REPAIR OR REPLACE FUEL LINE |
REPLACE AIR FUEL RATIO SENSOR
Replace the air fuel ratio sensor.
Result | ||
---|---|---|
|
NEXT |
CHECK WHETHER DTC OUTPUT RECURS (DTC P21951D, P219523, P21961D OR P219624)
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG) and turn the GTS 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 / 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 |