P0137 on Toyota 4Runner
Factory diagnostic protocol and troubleshooting wire for fault code P0137 specifically for the Toyota 4Runner (2020–2026, 4.0L V6 (1GR-FE) / 2.4L i-FORCE Turbo 4-Cyl).
1. Symptoms of P0137 on Toyota 4Runner
When the Engine Control Module (ECM/PCM) on your Toyota 4Runner (4.0L V6 (1GR-FE) / 2.4L i-FORCE Turbo 4-Cyl) logs fault code P0137, drivers commonly observe:
2. Most Likely Causes on Toyota 4Runner
Historical warranty claims and technical repair bulletins for Toyota 4Runner point to the following failure distribution:
3. Step-by-Step DIY Repair Guide for Toyota 4Runner
Listen for exhaust ticking or black soot around flex pipe, flanges, and sensor bungs before the catalytic converter. on the Toyota 4Runner equipped with 4.0L V6 (1GR-FE) / 2.4L i-FORCE Turbo 4-Cyl.
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 Toyota 4Runner equipped with 4.0L V6 (1GR-FE) / 2.4L i-FORCE Turbo 4-Cyl.
Unplug harness, remove old sensor with 7/8 socket, install replacement sensor and plug firmly. on the Toyota 4Runner equipped with 4.0L V6 (1GR-FE) / 2.4L i-FORCE Turbo 4-Cyl.
Clear DTCs and verify B1S2 holds steady between 0.45V and 0.75V during steady highway cruising. on the Toyota 4Runner equipped with 4.0L V6 (1GR-FE) / 2.4L i-FORCE Turbo 4-Cyl.
Equipment for Diagnosing Toyota 4Runner (P0137)
Toyota 4Runner OEM Replacement Sensor
Direct-fit replacement assembly engineered to OEM tolerances for Toyota 4Runner.
AstroAI Auto-Ranging Digital Multimeter
Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.
BlueDriver Bluetooth Pro OBDII Scan Tool
Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.
Other Common Fault Codes on Toyota 4Runner
Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Toyota 4Runner:
4. Toyota 4Runner P0137 FAQs
What causes code P0137 to trigger on a Toyota 4Runner?
On the Toyota 4Runner (4.0L V6 (1GR-FE) / 2.4L i-FORCE Turbo 4-Cyl), 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 Toyota 4Runner?
On the Toyota 4Runner, the 16-pin DLC diagnostic connector is located Lower dashboard near parking brake mechanism. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.
Can I safely drive my Toyota 4Runner 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.

