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.
Check Price on AmazonAffiliate link -- we earn a commission at no extra cost to you.
Shows real-time O2 sensor readings on your phone. See if the sensor is lazy, stuck, or actually working before spending money.
Check Price on AmazonAffiliate link -- we earn a commission at no extra cost to you.
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
Step-by-Step Diagnostic Procedure
-
Monitor bank 2 sensor 2 voltage on a scan tool. A fixed high reading (above 0.8V) indicates a rich condition or failed sensor.
-
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.
-
Inspect the sensor for contamination -- white residue (coolant) or oily deposits (burning oil).
-
Check the wiring for shorts to other power circuits or for chafed insulation.
-
Verify the connector is clean and free of moisture.
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 Motorcraft. 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.
Sources
This page is built from documented references. Verify against your own service info before repair work.
See All Codes & Fixes for Your Vehicle
Explore More
Was this helpful?
Share carcodefinder.com with a friend who needs to decode their check engine light.