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Toyota Camry XLS 2012 Error Code P0051: HO2S Heater Control Circuit Low Bank 2 Sensor 1 - Fix & Replacement Advice

Model: Unknown Fault Code: P0051 Posted: 2019-12-11 22:14

I own a 2012 Toyota Camry XLS with a 6-cylinder engine. Approximately two weeks ago, the check engine light activated. I visited three different auto parts stores to read the diagnostic codes, and all confirmed the same errors: - Error Code P0051: HO2S Heater Control Circuit Low (Bank 2 Sensor 1) - Error Code P2240: Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 2 Sensor 1) - Error Code P2241: Oxygen Sensor Pumping Current Circuit Low (A/F Sensor) Bank 2 Sensor 1 All three stores provided consistent readings, confirming the issue is not a reading error. I replaced the oxygen sensor with a BOSCH OEM-style unit. After test driving, the engine runs smoothly, but the check engine light remains on. I attempted to clear the codes by disconnecting the negative battery terminal, yet the warning light persists. My question: What am I missing? Is it possible that the issue lies not in the sensor itself, but in the heater circuit or wiring? Should I use an OBD2 scanner to reset the codes, or is there a deeper underlying problem? I suspect the BOSCH sensor may not be compatible with Toyota's system. Toyota typically recommends Denso sensors for optimal performance and compatibility. I'm now considering replacing it with a genuine Denso oxygen sensor.

Related fault codes

P0051

Comments (4)

Anonymous 2019-12-11 23:12

If the sensor and circuit are functioning properly, the ECM should automatically reset the code after a few driving cycles. However, in this case, the issue may stem from an incompatible replacement part. Toyota systems often require specific sensors like Denso for full compatibility. Check the heater circuit resistance and wiring integrity—this could be the root cause. Refer to rockauto.com for detailed diagrams and part references.

Anonymous 2019-12-12 13:54

Thanks for the clarification. This makes much more sense now. I initially thought a BOSCH sensor would work just as well, but it seems Toyota's system is sensitive to brand-specific components. I’ll verify voltage output on the heater circuit and ensure proper wiring connections. Going forward, I’ll stick with Denso or other Toyota-recommended sensors—this experience has taught me an important lesson about part compatibility.

Anonymous 2019-12-12 14:36

If the original oxygen sensor's heater element had a faulty resistance value, then even a new sensor may not resolve the issue. A proper diagnosis of the heater circuit’s electrical characteristics is essential before replacing the sensor.

Anonymous 2019-12-20 12:53

My frustration with Error Code P0051 is now fully resolved. The root cause was the BOSCH oxygen sensor I installed. Using a non-authorized brand like BOSCH—despite its price—did not resolve the issue. Toyota systems are designed to work best with OEM or recommended parts such as Denso. I’ve since replaced it with a genuine Denso O2 sensor, which fixed both the error code and the check engine light. Thanks, cj1, for pointing this out. The BOSCH sensor cost nearly twice as much as the Denso version—this experience clearly shows that saving money on aftermarket parts can backfire in critical systems like oxygen sensors. Case closed.