P0151 indicates the upstream oxygen sensor on engine bank 2 is detecting a voltage signal lower than the expected range. This suggests the air-fuel mixture is running too lean on that side of the engine, or the sensor circuit has an electrical fault. The powertrain control module sets this code when the voltage remains low for a predetermined amount of time.
The sensor internal element fails to generate proper voltage. This is the most common cause for this specific code.
Harness damage or corrosion can interrupt the signal path. Inspect for chafing near hot exhaust components.
Unmetered air entering the engine causes a genuine lean condition. This tricks the sensor into reading low voltage.
Outside air entering the exhaust stream before the sensor dilutes the reading. This mimics a lean condition to the control module.
Insufficient fuel delivery on bank 2 results in a lean mixture. Check fuel pressure and injector operation.
Internal processor failure preventing correct signal interpretation. This is statistically unlikely compared to sensor or wiring faults.
The definition is universal; the diagnostics are engine-specific. Open your vehicle for the codes documented for it:
Short-term driving is usually safe, but prolonged operation may damage the catalytic converter due to incorrect fuel trimming.
No, PCM failure is extremely rare for this code; focus on the sensor and wiring first.
Bank 2 refers to the side of the engine that does not contain cylinder number 1 on V-type engines.
No, clearing the code only resets the light; the underlying mechanical or electrical fault must be repaired.