Where is bank 2 sensor 1 on Lexus RX350?
Bank 2 Sensor 1 is the upstream oxygen sensor on the second exhaust bank, located before the catalytic converter.
On the Lexus RX 350, powered by the 3.5-liter V6 (2GR-FE), two exhaust banks share the system. Sensor 1 on Bank 2 monitors exhaust gas right after it leaves the engine on the bank opposite Bank 1. Access often requires faring or heat shield clearance, and you’ll typically find two upstream sensors (one per bank) and two downstream sensors (one per bank). For precise year-to-year location, consult the RX 350 service manual or a reliable wiring diagram, as layouts can vary slightly by model year.
Understanding the terminology
Bank 1 vs Bank 2
Bank 1 is the exhaust side that contains cylinder 1; Bank 2 is the opposite side. Sensor 1 on either bank is the upstream oxygen sensor (before the catalytic converter), while Sensor 2 on that bank is downstream (after the converter).
How to locate Bank 2 Sensor 1 on the RX 350
To locate Bank 2 Sensor 1, follow these steps. This practical guide helps identify the correct sensor without guesswork.
Here is how to pinpoint the correct sensor on the RX 350’s exhaust system:
- Identify the two upstream O2 sensors near the exhaust manifolds; each bank has its own upstream sensor closer to the engine.
- Determine which bank is Bank 2 by cylinder numbering in your service manual or a trusted diagram (Bank 2 is the bank that does not contain cylinder 1).
- Locate the upstream sensor on that bank—the sensor screwed into the exhaust manifold on that bank before the catalytic converter.
- Follow the sensor’s wiring harness toward the engine bay; the connector is typically a four-wire plug with a locking tab.
- If you can’t see it from above, you may need to remove a heat shield, loosen a duct, or temporarily clear space to access the sensor.
When you’ve identified Bank 2 Sensor 1, you can proceed with testing, cleaning, or replacement following the manufacturer’s torque specs and procedures.
Summary
Bank 2 Sensor 1 on the Lexus RX 350 is the upstream O2 sensor installed on the second exhaust bank, before the catalytic converter. It sits in the exhaust manifold on that bank and is accessible from the engine bay, though some model years may require heat shield removal or minor disassembly for full access. Always verify with your vehicle’s documentation and practice safe handling when working near hot exhaust components.
