Toyota Engine Bank 1 and Bank 2 A/F and O2 Identification

This page provides information on the proper identification of engine bank 1 and engine bank 2 for correct A/F sensor and oxygen sensor replacement. Contains information that identifies engine bank 1 and engine bank 2 on the following engines: 1AZ-FE, 2AZ-FE, 2AZ-FE (PZEV), 1GR-FE, 2GR-FE, 2JZ-GE, 1MZ-FE, 3MZ-FE, 1UR-FE, 3UR-FE, 2UZ-FE, 5VZ-FE, and 1ZZ-FE.

Bank 1 (B1) refers to the bank that includes cylinder No. 1.

Bank 2 (B2) refers to the bank opposite bank 1.

Sensor 1 (S1) refers to the sensor that is located before the catalytic converters.

Sensor 2 (S2) refers to the sensor that is located after the catalytic converters.

Toyota Applicable Vehicles:

OBDII Components

• Camshaft Position Sensor
• Catalytic Converter
• Engine Coolant Temperature (ECT) Sensor
• Crankshaft Position Sensor
• Evaporative Emission (EVAP) System
• Exhaust Gas Recirculation (EGR)
• Intake Air Temperature (IAT) Sensor
• Knock Sensor (KS)
• Manifold Absolute Pressure (MAP) Sensor
• Mass Air Flow (MAF) Sensor
• Oxygen Sensor (O2S) - Air/Fuel (A/F) Sensor
• Positive Crankcase Ventilation (PCV)
• Thermostat
• Throttle Position Sensor (TPS)
• Vehicle Speed Sensors (VSS)

On-Board Diagnostic (OBDII) System FAQ

• 5 Most Common Reasons for a Check Engine Light
• Latest 15 Codes Updated
• Top 25 Engine Codes
• Honda B-CAN And F-CAN
• Oxygen Sensor Location
• What is OBDII?
• How does the OBDII works?
• Why is the Engine Light ON?
• OBDII Pending And Active Codes
• How to Reset the Check Engine Light
• Is the OBD system working correctly?
• What does it mean if the Service Engine Soon or Check Engine light is blinking?
• What does it mean if the Service Engine Soon or Check Engine turns on while I'm driving?
• What should I do if the Service Engine Soon or Check Engine light stays on?
• What is Bank 1 and Bank 2?
• Difference Between Open Loop and Close Loop
• What is ECM?
• What is PCM?
• What Is Technical Service Bulletins?
• Vehicle Identification Number VIN Decoder
• 1993-2010 Toyota Oxygen (O2) Sensor Identification

Related Information

• Find a Shop
• Car Questions
• Cars TSB
• Cars Recalls
• Cars Common Problems
• Cars Safety Rating
• Cars Technical Articles
• OBDII FAQ
• OBDII Components
• Car Glossary
• Car Warning Lights
• Cars MPG
• 2023 Cars MPG
• Car Test Game
• What is OBDII?
• How does the OBDII works?
• Why is the Engine Light ON?
• How to Reset MIL
• 5 Most Common Reasons for Check Engine Light
• Top 25 Engine Codes
• Latest 15 Codes Updated
• All OBDII Codes
• Powertrain (P) Codes
• Network (U) Codes
• Body (B) Codes
• Chassis (C) Codes