O2 Sensor Circuit High Voltage (Bank 2 Sensor 2)
The P0158 code means the vehicle's onboard diagnostic system has detected: O2 Sensor Circuit High Voltage (Bank 2 Sensor 2). This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $80 - $300 (O2 sensor $60-$200; labor $50-$150)
Test O2 sensor voltage (should fluctuate 0.1-0.9V). Do not replace a $150 sensor without confirming it is actually bad first.
Shows real-time O2 sensor readings on your phone. See if the sensor is lazy, stuck, or actually working before spending money.
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Common Symptoms
- Check Engine Light on
- No significant drivability issues
- Slightly increased emissions
- Catalyst monitoring may not complete
- Possible emissions test failure
Probable Causes (Ranked by Likelihood)
- Failed downstream O2 sensor stuck reading rich Very High
- Short to power in the sensor signal wiring High
- Contaminated sensor from oil or coolant Moderate
- Corroded connector causing signal interference Moderate
- Failing catalytic converter on bank 2 Low
Common Fixes by Vehicle
What techs usually find when diagnosing P0158 on specific vehicles — tap your vehicle for the fix and the exact part:
2005-2015 Toyota 3.5L 2GR-FE (Camry V6, Avalon, RX350) easy DIY
Replace Bank 2 Sensor 2 (downstream, passenger side post-cat). High voltage usually means a rich condition upstream OR a failed sensor. Check long-term fuel trims on Bank 2 first -- if >+10%, fix the fuel trim issue before replacing the sensor.
Labor: 30 min2003-2014 Nissan 3.5L VQ35 (Murano, Maxima, 350Z) easy DIY
Replace B2S2 downstream O2. Nissan VQ post-cat sensors get coated with pre-cat debris when internal ceramic breaks up -- always inspect both pre-cats by removing and shaking. Debris means catalyst replacement is next.
Labor: 45 min2007-2016 Ford F-150 5.4L/6.2L V8 easy DIY
Replace Bank 2 Sensor 2 with an OE-quality Motorcraft unit. If B2S2 reads high continuously, verify no exhaust leak between the cat and sensor. Also check the fuel pressure regulator -- stuck-closed regulator on 5.4L 3V causes rich B2 trims.
Labor: 30 minFrequently Asked Questions
Can I drive with code P0158?
Yes, you can drive normally. The downstream sensor on bank 2 is a monitoring sensor only and does not control fuel delivery.
What causes high voltage on a downstream O2 sensor?
High voltage means the sensor is detecting a rich exhaust condition after the catalytic converter. This is usually caused by a failed sensor, a contaminated sensing element, or in rare cases a failing catalytic converter that is not properly oxidizing exhaust gases.
Is P0158 the bank 2 version of P0138?
Yes. P0138 is high voltage on bank 1 sensor 2, and P0158 is the same fault on bank 2 sensor 2.
What actually makes the computer set an oxygen sensor code?
The OBD II regulation requires four separate detections for an oxygen sensor (Title 13 CCR 1968.2, section (e)(7.2)): deterioration in voltage, response rate or amplitude that would push emissions past 1.5 times the FTP standards; loss of circuit continuity; out-of-range values; and the case where the sensor has degraded enough that the fuel system stops using it and falls back to open loop. A sensor can therefore set a code while still producing a signal that looks plausible on a scan tool. This is the threshold the monitor is designed around, not a description of your specific fault — the regulation says what the system must detect, not how to find it on your vehicle.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
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Monitor bank 2 sensor 2 voltage on a scan tool. A fixed high reading (above 0.8V) indicates a rich condition or failed sensor.
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Disconnect the sensor and check if the voltage drops. If it does, the sensor is at fault. If it remains high, check for a wiring short to power.
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Inspect the sensor for contamination -- white residue (coolant) or oily deposits (burning oil).
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Check the wiring for shorts to other power circuits or for chafed insulation.
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Verify the connector is clean and free of moisture.
Sources 3
This page is built from documented references. Verify against your own service info before repair work.
- California Code of Regulations, Title 13 section 1968.2 (OBD II)malfunction criteria, section (e)
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- 2007-2015 Toyota Tundra (5.7L V8)
- 2005-2013 Nissan Xterra (4.0L V6)
- 2008-2017 Honda Odyssey (3.5L V6)
- 2009-2016 Chevrolet Traverse (3.6L V6)
- 2010-2018 Ford Explorer (3.5L V6)
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