What it means
NOx Sensor Circuit Low (Bank 2): the signal voltage is below the expected range. Often a short to ground or high resistance in the wiring.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The bank 2 NOx sensor sends an electrical signal to the emissions control module. P2215 sets when that signal falls below the expected range, which can happen if the signal wire is shorted to ground, has high resistance, or loses a sound connection.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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
- Record freeze-frame data and check live bank 2 NOx sensor status to confirm the low signal and when it occurs.
- Inspect the bank 2 sensor connector for corrosion, moisture, loose pins, or damaged terminals.
- Trace the bank 2 signal harness for chafing, melted insulation, or contact with ground or exhaust components.
- Check signal circuit continuity and shorts to ground using the wiring diagram, comparing results with the manufacturer's specification.
- If wiring and connections pass, test the bank 2 NOx sensor output and its power and ground according to the manufacturer's procedure.
Common fixes
- Clean or repair corroded bank 2 sensor connector terminals.
- Repair a signal wire short to ground or a high-resistance connection.
- Replace damaged sections of the bank 2 sensor harness.
- Replace the bank 2 NOx sensor if its signal remains low with a verified circuit.
Can I keep driving?
If the vehicle runs normally, a short trip may be possible, but a low bank 2 signal can prevent proper NOx monitoring and may lead to an AdBlue/DEF warning or start countdown. Avoid extended driving and do not ignore a countdown.
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.