P0051: O2 Sensor Heater Control Circuit Low — Bank 2 Sensor 1
What to do
No urgent driveability impact. Will fail an emissions test until repaired.
What this code means
The bank 2 upstream sensor heater circuit is reading low — a short to ground, or a heater element failed short. Where both banks report low heater circuits at once, suspect the shared supply or ground rather than two sensors failing together.
Likely causes
Start here
- Failed oxygen sensor heater element · easy
- Wiring shorted to ground · moderate
- Corroded or loose connector · easy
Less common
- Exhaust heat damage to sensor harness · moderate
Symptoms
Components involved
Information, not instruction
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Community experience
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