P0050: O2 Sensor Heater Control Circuit — Bank 2 Sensor 1
What to do
No urgent driveability impact. It will fail an emissions test and slightly worsen economy on short trips.
What this code means
A heater circuit fault on the upstream oxygen sensor of bank 2. Bank 2 is the bank without cylinder 1, and on transverse engines it is usually the rear bank against the bulkhead — the harder of the two to reach, which is worth knowing before quoting the job. Electrically the diagnosis is identical to its bank 1 counterpart P0030.
Likely causes
Start here
Less common
- Open circuit in heater wiring · moderate
- Exhaust heat damage to sensor harness · moderate
Rare
- Control module driver failure · specialist
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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