A25A-FXS (ENGINE CONTROL): SFI SYSTEM: P223711,P223712,P223713,P223716,P223717,P22371B,P225111,P225112; A/F (O2) Sensor Positive Current Control Bank 1 Sensor 1 Circuit Short to Ground; 2020 - 2022 MY Avalon HV [08/2019

Although the DTC titles say O2 sensor, these DTCs relate to the air fuel ratio sensor (sensor 1).

MONITOR DESCRIPTION

These DTCs are stored when there is an open or short in the air fuel ratio sensor (sensor 1) circuit, or the air fuel ratio sensor (sensor 1) output value is abnormal. The voltage of the air fuel ratio sensor (sensor 1) is monitored while the power switch is on (IG), and the impedance (impedance is an electrical term that indicates the difficulty of flow of current) is checked while engine running. If the voltage of the air fuel ratio sensor (sensor 1) is outside the normal range, or the impedance is outside the normal range, the ECM illuminates the MIL and stores a DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

P2237 and P2238

P2239, P2252 and P2253

P2237: Air Fuel Ratio Sensor (Sensor 1) Circuit Continuity Check (Circuit Open)

P2238: Air Fuel Ratio Sensor (Sensor 1) Impedance Check (High Impedance)

P2238 and P2239: Air Fuel Ratio Sensor (Sensor 1) Range Check (A1A+ Low Voltage, A1A+ High Voltage)

P2238 and P2239: Air Fuel Ratio Sensor (Sensor 1) Correlation (A1A+ and A1A-)

P2252 and P2253: Air Fuel Ratio Sensor (Sensor 1) Range Check (A1A- Low Voltage, A1A- High Voltage)

TYPICAL MALFUNCTION THRESHOLDS

P2237: Air Fuel Ratio Sensor (Sensor 1) Circuit Continuity Check (Circuit Open)

P2238: Air Fuel Ratio Sensor (Sensor 1) Impedance Check (High Impedance)

P2238: Air Fuel Ratio Sensor (Sensor 1) Range Check (A1A+ Low Voltage)

P2238: Air Fuel Ratio Sensor (Sensor 1) Correlation (A1A+ and A1A-)

P2239: Air Fuel Ratio Sensor (Sensor 1) Range Check (A1A+ High Voltage)

P2239: Air Fuel Ratio Sensor (Sensor 1) Correlation (A1A+ and A1A-)

P2252: Air Fuel Ratio Sensor (Sensor 1) Range Check (A1A- Low Voltage)

P2253: Air Fuel Ratio Sensor (Sensor 1) Range Check (A1A- High Voltage)

CONFIRMATION DRIVING PATTERN

HINT:

After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.
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When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.
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Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream 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.
Put the engine in Inspection Mode (Maintenance Mode).
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Start the engine and wait 5 minutes or more [A].
Turn the Techstream on.
Enter the following menus: Powertrain / Engine / Trouble Codes [B].
Read the pending DTCs.
HINT:
- 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: P223711, P223712, P223713, P223716, P223717, P22371B, P225111 or P225112.

Check the DTC judgment result.

Techstream 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

HINT:

If the judgment result is NORMAL, the system is normal.
If the judgment result is ABNORMAL, the system has a malfunction.
If the judgment result is INCOMPLETE, idle the engine for 5 minutes and check the DTC judgment result again.
[A] to [B]: Normal judgment procedure.
The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.
When clearing the permanent DTCs, do not disconnect the cable from the auxiliary battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.
Vehicle Control History may be stored in the hybrid vehicle control ECU assembly if the engine is malfunctioning. Certain vehicle condition information is recorded when Vehicle Control History is stored. Reading the vehicle conditions recorded in both the Freeze Frame Data and Vehicle Control History can be useful for troubleshooting.
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(Select Powertrain in Health Check and then check the time stamp data.)

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If any "Engine Malfunction" Vehicle Control History item has been stored in the hybrid vehicle control ECU assembly, make sure to clear it. However, as all Vehicle Control History items are cleared simultaneously, if any Vehicle Control History items other than "Engine Malfunction" are stored, make sure to perform any troubleshooting for them before clearing Vehicle Control History.
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HINT:

Sensor 1 refers to the sensor closest to the engine assembly.
Sensor 2 refers to the sensor farthest away from the engine assembly.
Refer to "Data List / Active Test" [A/F (O2) Sensor Current B1S1].
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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 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

Make sure that the connector is properly connected. If it is not, securely connect it and check for DTCs again.

Perform "Inspection After Repair" after replacing the air fuel ratio sensor (sensor 1).