OBD code P0151

The bank 2 upstream oxygen sensor is persistently reporting a low-voltage signal, interpreted as a very lean mixture.

Estimated severity

Medium

Common symptoms

Possible hesitation or power loss if the mixture is genuinely lean
Check engine light on
Higher fuel consumption due to ECU corrections

Likely causes

Faulty bank 2 oxygen sensor
Exhaust leaks before the bank 2 sensor
Lean mixture issue on bank 2, similar to P0174

Recommended checks

1. Check whether P0174 or other bank 2 mixture codes are also present.
2. Inspect for exhaust leaks around bank 2.
3. Use a scanner to analyze the sensor behavior, including switching and voltage range.
4. If everything else is correct, replace the oxygen sensor.

What does code P0151 mean?

Code P0151 means the oxygen sensor before the catalytic converter on bank 2 stays at low voltage for too long. The ECU interprets this as a very lean condition. The cause may be the sensor itself, an exhaust leak or an actual lean mixture on that bank.

Try assisted diagnostics