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P0137 on Lexus RX

O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)

Factory diagnostic protocol and troubleshooting wire for fault code P0137 specifically for the Lexus RX (2020–2026, 2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP)).

Verified OEM Telemetry & Field Repair Tree
Lexus RX2020–2026
Lexus RX
SUV2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP)
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
RX SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Drivable (Short Trip)
Low urgency level
Est. Repair Cost
$100 - $300 (DIY: $35 - $100)
Parts & Labor DIY
Check P0137 On Another Lexus Model:
Diagnose P0137 on Specific RX Model Year:

1. Symptoms of P0137 on Lexus RX

When the Engine Control Module (ECM/PCM) on your Lexus RX (2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP)) logs fault code P0137, drivers commonly observe:

Check Engine Light on on Lexus RX (2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP))
Downstream sensor voltage consistently below 0.15V on scan tool on Lexus RX (2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP))
Failed emissions test on Lexus RX (2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP))
Lexus RX OBD-II Port Location
The 16-pin diagnostic connector is located Driver footwell above brake pedal assembly. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Lexus RX

Historical warranty claims and technical repair bulletins for Lexus RX point to the following failure distribution:

55%
Exhaust leak upstream of or directly at the Sensor 2 bung letting in fresh air (Lexus OEM Part)
25%
Faulty downstream oxygen sensor (Lexus OEM Part)
12%
Short to ground in sensor signal wire (Lexus OEM Part)
8%
Extremely lean exhaust condition (Lexus OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Lexus RX.

3. Step-by-Step DIY Repair Guide for Lexus RX

01
Inspect Exhaust System for Leaks

Listen for exhaust ticking or black soot around flex pipe, flanges, and sensor bungs before the catalytic converter. on the Lexus RX equipped with 2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP).

Required Tool: Flashlight, Jack Stands
02
Check Sensor Signal Voltage with Scan Tool

Monitor B1S2 voltage. Snap the throttle to enrich mixture; voltage should briefly spike above 0.8V. If it remains 0.0V–0.1V, sensor is defective or shorted. on the Lexus RX equipped with 2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP).

Required Tool: OBD-II Scanner
03
Replace Downstream O2 Sensor

Unplug harness, remove old sensor with 7/8 socket, install replacement sensor and plug firmly. on the Lexus RX equipped with 2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP).

Required Tool: O2 Sensor Socket, Ratchet
04
Clear Codes

Clear DTCs and verify B1S2 holds steady between 0.45V and 0.75V during steady highway cruising. on the Lexus RX equipped with 2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP).

Required Tool: OBD-II Scanner
Recommended Parts & Testing Tools

Equipment for Diagnosing Lexus RX (P0137)

Prime Fast Delivery & Verified Fitment
Direct-Fit Replacement Part

Lexus RX OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

Direct-fit replacement assembly engineered to OEM tolerances for Lexus RX.

$45 – $95 Prime
Check Fitment on Amazon
Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

4.6 / 5.0 (Best Seller)

Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.

$29.99 Prime
View on Amazon
Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

4.7 / 5.0 (50,000+ Reviews)

Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

Compare OEM & Aftermarket Replacement Sensors for Lexus RXVerified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
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Other Common Fault Codes on Lexus RX

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Lexus RX:

4. Lexus RX P0137 FAQs

What causes code P0137 to trigger on a Lexus RX?

On the Lexus RX (2.4L Turbo (RX 350 275HP) / 2.5L Hybrid / 2.4L Turbo Performance Hybrid (RX 500h 366HP)), P0137 is most frequently caused by Exhaust leak upstream of or directly at the Sensor 2 bung letting in fresh air or Faulty downstream oxygen sensor.

Where is the OBD-II port located on my Lexus RX?

On the Lexus RX, the 16-pin DLC diagnostic connector is located Driver footwell above brake pedal assembly. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Lexus RX with code P0137?

Yes. Vehicle is fully drivable, but Check Engine Light will remain illuminated. Given that P0137 carries a Low severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.