What it means
Heater control of bank 1 sensor 2 is electrically OK but does not heat the sensor as expected — element aged or wiring resistance high.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The heater warms the bank 1 sensor 2 oxygen sensor so it can measure exhaust oxygen promptly; this is the downstream sensor after the catalytic converter on bank 1. The control module monitors heater operation and sets P00D2 when the heater circuit appears electrically connected but the sensor does not warm as expected.
Common causes
Most likely first.
- HO2S heater element fault
- Open or high-resistance heater wiring or connection
- Fault in the heater control circuit
Symptoms
- Check engine light on
- Possible rough running while the engine is cold
- Fuel economy may worsen
- Emissions test may be affected
How to diagnose it
- Record freeze-frame data and check how quickly bank 1 sensor 2 begins reporting usable oxygen data after a cold start.
- Locate the downstream bank 1 oxygen sensor and inspect its heater connector and exhaust-area wiring for heat damage, corrosion, looseness, or chafing.
- Check for related heater-circuit codes that could point to a shared power supply or control problem.
- Test the bank 1 sensor 2 heater element and its supply, ground, and control circuit using the manufacturer's procedure.
- Compare heater operation with the manufacturer's specification before deciding whether the fault is in the sensor or its wiring.
Common fixes
- Repair damaged or chafed bank 1 sensor 2 heater wiring.
- Clean or repair a loose or corroded heater connector.
- Repair a confirmed heater supply or control-circuit fault.
- Replace the bank 1 sensor 2 oxygen sensor if its heater element fails testing.
Can I keep driving?
You can usually drive gently if the engine runs normally, but emissions may rise and an emissions test may be affected. Avoid ignoring it if other symptoms appear, since the fault can complicate diagnosis of catalytic-converter performance.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.