P0059
HO2S Heater Resistance Bank 2 Sensor 1
Emissions / O2 sensor
Generic OBD-II
Medium
What it means
P0059 means the heater element inside the upstream (bank 2, sensor 1) oxygen sensor is reading a resistance outside the normal range — the ECM measures the heater and sees it as too high or too low. This almost always means the sensor's internal heater has failed, so the O2 sensor warms up too slowly and closed-loop fuel control is delayed.
Medium
Can I keep driving? Safe to drive, but it will fail emissions and slightly hurt cold-start economy; plan to replace the sensor.
Common symptoms
What you'll notice
- Check-engine light on
- Delayed closed-loop fuel control after start-up
- Slightly worse cold-start fuel economy
- Failed emissions test
Common causes
Most likely first
- Failed heater element inside the O2 sensor (most common by far)Likely
- Corroded or poor connector at the sensorCommon
- Heater circuit wiring faultCommon
- Blown heater fuseLess often
- Failed ECM driver (rare)Less often
How to diagnose & fix
Work through it in order
- Scan and record freeze-frame data.
- Inspect the sensor connector for corrosion or looseness.
- Measure the heater's resistance across the sensor terminals against spec.
- Check the heater's power feed and fuse.
- Replace the O2 sensor — the heater isn't separately serviceable; consider the ECM last. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0059?+
Yes. The heater only helps the sensor warm up, so the engine runs normally, but the car will fail emissions and cold-start fueling is slightly less efficient.
Can I just clear P0059?+
It returns because the heater resistance is genuinely out of range. That almost always means the O2 sensor's internal heater has failed and the sensor needs replacing.
Related codes
Often seen with P0059
Read & clear P0059 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