P0056: O2 Sensor Heater Control Circuit — Bank 2 Sensor 2
What to do
No driveability impact. Blocks emissions readiness until repaired.
What this code means
A heater circuit fault on the bank 2 downstream sensor, after that bank's catalytic converter. As with all downstream sensors, its harness runs under the vehicle and takes the worst of the weather — corrosion and stone damage lead the list well ahead of element failure.
Likely causes
Start here
- Corroded or loose connector · easy
- Failed oxygen sensor heater element · easy
- Road damage to underfloor wiring · moderate
Less common
- Open circuit in heater wiring · moderate
- Blown fuse supplying the heater circuit · easy
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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