What it means
The heater inside the bank 1 NOx sensor cannot be controlled — open, short, or failed driver. Without proper heater operation the sensor never reaches its operating temperature and reports invalid data.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The bank 1 NOx sensor has an internal heater that brings its measuring element up to operating temperature. The control module monitors the heater circuit and sets P2205 when it detects an electrical fault such as an open circuit or short, so the sensor may not warm up and provide usable readings.
Common causes
Most likely first.
- Heater element open
- Heater short to supply or ground
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
How to diagnose it
- Check freeze-frame data and scan for related NOx sensor, heater, fuse, or module codes to see when the bank 1 fault occurs.
- Identify the bank 1 NOx sensor using vehicle information, then inspect its connector and heat-exposed wiring for looseness, corrosion, melting, or damage.
- Check the heater fuse and power and ground connections for the bank 1 sensor, following the vehicle wiring diagram.
- With the circuit safely disconnected as specified by the manufacturer, test the heater element and wiring for an open or short against the manufacturer's specification.
- If wiring and heater tests pass, check the module's heater command and feedback with a scan tool or circuit test before suspecting a failed control driver.
Common fixes
- Reconnect or clean a loose or corroded bank 1 NOx sensor connector.
- Repair damaged or shorted heater wiring near the exhaust.
- Replace a failed heater fuse after checking for the cause of the failure.
- Replace the bank 1 NOx sensor if its heater element is open or shorted.
- Repair the heater control driver only if circuit tests confirm a module fault.
Can I keep driving?
The vehicle may remain drivable, but emissions control and NOx readings can be unreliable, and an emissions test may fail. If an AdBlue/DEF warning or start countdown appears, address the fault promptly because the countdown can eventually prevent restarting.
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.