OBD-II diagnostic trouble code
P0156Caution
O2 Sensor Circuit Malfunction (Bank 2 Sensor 2)
The rear bank-2 oxygen sensor isn't producing a usable signal, the bank-2 mirror of the same rear-sensor fault seen in P0137/P0138.
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Code names are compiled from open/standardized SAE and ISO references. Explanations, symptoms, causes and fixes are original. Covers generic (P0/C0/B0/U0) codes only — manufacturer-specific codes are planned for a future update.
Frequently asked questions
Can I drive with P0156?
You can usually keep driving with P0156, but don't put it off — the underlying cause can get worse or lead to further damage the longer it goes unaddressed. Get it diagnosed as soon as you reasonably can.
How much does it cost to fix P0156?
The cost varies too much by cause and vehicle to give a single figure here — a diagnosis will narrow it down.
What causes P0156?
Reviewed by Artyom SemenovAutomotive Editor · Fact-checked by Yauheni Kapliarchuk, Editor-in-Chief