P0063
HO2S Heater Control Circuit Low Bank 2 Sensor 3
Emissions / O2 sensor
Generic OBD-II
Medium
What it means
P0063 means the heater control circuit for the bank 2, sensor 3 oxygen sensor is reading low voltage — typically a short to ground, an open in the wiring, or a failed heater element. Sensor 3 is a downstream (post-catalyst) O2 sensor used mainly to monitor the catalytic converter, so drivability is rarely affected even though the light is on.
Medium
Can I keep driving? Safe to drive — this is a downstream monitoring sensor, so there's little performance impact, but it keeps the light on and can block emissions readiness.
Common symptoms
What you'll notice
- Check-engine light on
- Emissions readiness monitors won't complete
- Failed emissions test
- Little to no change in how the car drives
Common causes
Most likely first
- Failed heater element inside the O2 sensorLikely
- Short to ground or open in the heater wiringCommon
- Corroded or loose connector at the sensorCommon
- Blown fuse or poor groundLess often
- Failed ECM driver (rare)Less often
How to diagnose & fix
Work through it in order
- Scan and record freeze-frame data.
- Check the O2 sensor heater fuse.
- Inspect the connector and wiring for a short to ground or an open.
- Measure the heater's resistance against spec.
- Replace the O2 sensor if the heater is open; consider the ECM last. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0063?+
Yes. Sensor 3 is a downstream (post-catalyst) sensor used mainly to monitor the converter, so drivability is barely affected — but the light stays on.
Can I just clear P0063?+
It returns until the heater or wiring is repaired. A failed heater element means replacing the O2 sensor; the readiness monitor won't set until it's fixed.
Related codes
Often seen with P0063
Read & clear P0063 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX