P0158: O2 Sensor Circuit High Voltage — Bank 2 Sensor 2
What to do
Usually no driveability impact. Worsening economy alongside this code points upstream at fuelling rather than at this sensor.
What this code means
The downstream bank 2 sensor is reporting persistently high voltage — a short to supply, or a genuinely rich exhaust reaching the rear of the system. If economy has also worsened, the rich condition is likely real and belongs upstream.
Likely causes
Start here
- Faulty oxygen sensor · easy
- Wiring shorted to voltage · moderate
Less common
- Leaking fuel injector · moderate
- Excessive fuel pressure · moderate
- Corroded or loose connector · easy
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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