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P0137 on Lexus: Symptoms, Causes & Fix

O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)

Official technical diagnostic wire for fault code P0137 specifically affecting Lexus vehicles (ES, RX, NX, GX, LX).

Sensor Voltage Ref
0.1V – 5.0V Ref
Lexus Factory Standard
CAN Bus Speed
500 kbps CAN-FD
ISO 15765-4 Diagnostic Bus
Drivability Status
Drivable (Short Trip)
Low urgency level
Est. Repair Cost
$100 - $300 (DIY: $35 - $100)
Parts & Labor DIY
Model-Specific Diagnostic Wires

Select Your Lexus Model for P0137:

6 Models Available

1. Common Symptoms on Lexus Vehicles

When Lexus Engine Control Modules (ECM) trigger fault code P0137, drivers typically report:

Check Engine Light on on Lexus Powertrains
Downstream sensor voltage consistently below 0.15V on scan tool on Lexus Powertrains
Failed emissions test on Lexus Powertrains

2. Root Causes on Lexus Engines

Historical diagnostic claims across Lexus engines 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)

3. Step-by-Step Fix Protocol for Lexus

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 Lexus engines.

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 Lexus engines.

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 Lexus engines.

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 Lexus engines.

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

Equipment for Diagnosing Lexus (P0137)

Prime Fast Delivery & Verified Fitment
Direct-Fit Replacement Part

Lexus OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

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

$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 LexusVerified direct-fit pricing from Denso, Bosch, Motorcraft, and ACDelco on Amazon.
Find Parts on Amazon
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4. Lexus P0137 Frequently Asked Questions

What does code P0137 mean on a Lexus?

On Lexus vehicles, P0137 indicates that the Engine Control Module (ECM) detected o2 sensor circuit low voltage (bank 1 sensor 2). This typically points to Exhaust leak upstream of or directly at the Sensor 2 bung letting in fresh air or Faulty downstream oxygen sensor.

Can I continue driving my Lexus with code P0137?

Yes. Vehicle is fully drivable, but Check Engine Light will remain illuminated. Because this code carries a Low severity rating on Lexus powertrains, we recommend scanning live data values promptly to prevent secondary damage.

How much does it cost to fix code P0137 on a Lexus?

Estimated DIY parts cost ranges from $100 - $300 (DIY: $35 - $100), while professional shop repairs at an authorized Lexus dealership or independent specialist typically range from $180 to $380 including diagnostic labor.