P0157
Low SeverityO2 Sensor Circuit Low Voltage (Bank 2, Sensor 2)
Emissions System
What Does P0157 Mean?
Downstream O2 sensor bank 2 reads low voltage.
Common Fix
Replace downstream O2 sensor
Estimated Cost (DIY)
$25 - $80
Symptoms
- ⚠️Check engine light
- ⚠️Failed emissions
Common Causes
Failed sensorlikely
Exhaust leak after catpossible
How to Diagnose P0157
- 1Monitor sensor voltage
- 2Check for exhaust leaks
- 3Replace sensor
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Frequently Asked Questions
- Is P0157 just like P0137?
- Yes — same problem, other bank. P0137 is bank 1, P0157 is bank 2.
- Do I need to fix this?
- Only needed for emissions testing. No driveability impact.