What it means
A general electrical fault on the heater of the bank 2 NOx sensor. NOx sensors must reach roughly 800 C to measure correctly; without heater current the sensor never enters its operating range.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The bank 1 sensor 1 NOx sensor has a heater circuit with a feedback, or sense, path that lets the control module monitor heater operation. P2208 indicates an electrical fault in that sense circuit, so the module may not be able to verify that the sensor is heating correctly.
Common causes
Most likely first.
- Heater element failed
- Heater wiring open or connector loose
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
- Read freeze-frame data and related codes to establish when the bank 1 sensor 1 heater sense fault was detected.
- Confirm the bank 1 sensor 1 location from vehicle-specific information, then inspect its connector and sense wiring for corrosion, looseness, heat damage, or an open.
- Check the sensor's heater fuse, supply, and ground using the vehicle wiring diagram to rule out a shared power problem.
- Test the sense wire and heater connections for continuity, shorts, and terminal contact according to the manufacturer's procedure.
- If the harness passes, compare heater command and sense feedback on a scan tool and test the sensor or module circuit against the manufacturer's specification.
Common fixes
- Reconnect or clean the bank 1 sensor 1 connector.
- Repair an open, short, or heat-damaged section of the heater sense wiring.
- Restore a faulty fuse, power feed, or ground connection identified in testing.
- Replace the bank 1 sensor 1 NOx sensor if its heater or feedback circuit fails specified tests.
- Repair the control module only if circuit checks confirm a module fault.
Can I keep driving?
The vehicle may drive, but the emissions system may lack reliable feedback for the bank 1 sensor 1 heater, so NOx control and inspection results can suffer. If DEF warnings or a no-start countdown appear, arrange repair soon.
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.