P0158
O2 Sensor Circuit High Voltage Bank 2 Sensor 2
Fuel & air metering
Generic OBD-II
Medium
What it means
P0158 means the downstream oxygen sensor on bank 2 (sensor 2, after the catalytic converter) is sending an abnormally high voltage. That usually indicates a wiring short to voltage or a failing sensor, though a genuinely rich-running engine can also drive the signal high. The car typically drives fine, but it affects emissions monitoring and fuel-trim accuracy.
Medium
Can I keep driving? Usually safe to drive — this is a downstream oxygen-sensor circuit fault that mainly affects emissions and fine fuel control, not starting.
Common symptoms
What you'll notice
- Check-engine light on
- Often little or no change in drivability
- Possible slightly rich running or minor fuel-economy loss
- May fail an emissions test
Common causes
Most likely first
- Signal wire shorted to voltage or a chafed harnessLikely
- Faulty oxygen sensor (bank 2, sensor 2)Common
- Corroded or loose connector at the sensorCommon
- Engine genuinely running rich (check fuel trims)Less often
- Faulty ECM/PCM (rare — rule out wiring and sensor first)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check fuel-trim values for a real rich condition.
- Inspect the sensor signal wiring for a short to voltage or damage.
- Check the connector for corrosion or looseness.
- View the sensor voltage on a scan tool — stuck high points to a circuit or sensor fault.
- Replace bank 2 sensor 2 if it's at fault; repair wiring as needed. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0158?+
Generally yes for normal driving — it's a downstream sensor circuit fault. Fix it to keep fuel control accurate and to pass emissions.
Can I just clear P0158?+
It returns once the ECM sees the high voltage again. Repair the wiring or sensor, or address a rich-running cause, first.
Related codes
Often seen with P0158
Read & clear P0158 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX