P2215: NOx Sensor Circuit Low (Bank 2)

P2215 says the NOx value transmitted for bank 2 falls below the smallest figure a healthy sensor can deliver. Because smart NOx sensors talk over CAN, the limit is a concentration in ppm, not a wire voltage. No manufacturer publishes this bank 2 code; the diesels on record send both banks through one SCR system and use P2202 instead. Those bank 1 limits give the scale: GM's 6.6L and 3.0L Duramax flag readings below minus 90 ppm (on the LZ0 only after the dew point is reached, Type B over two trips), VW's 2014 Touareg TDI below minus 105 ppm. A strongly negative value usually comes from a drifted element or a fault inside the sensor electronics. P2216 is the high limit, P2213 the general circuit fault.

Bank 2 is the side without cylinder 1, so it only exists on V or boxer engines.

Symptoms

• Malfunction indicator lamp on
• Negative NOx value for bank 2 in live data
• DEF dosing switches to a substitute strategy

Most likely causes

• NOx element of the bank 2 sensor drifted low
• Fault in the measuring electronics of the sensor module
• Damaged lead between probe and sensor module

What to check, in order

Start with the simplest. You can tick off each step.

1. Read the codes and the NOx data before and after the SCR catalyst
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Check the sensor's connector and wiring
4. Look for exhaust leaks ahead of the sensor
5. Confirm that the AdBlue/DEF is of good quality
6. Replace the sensor only after ruling out power, ground, and leaks

Good to know

• Repair difficulty: medium
• It affects emissions.

What each character of P2215 means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 2: Fuel injection
• 15: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2215?

You can usually keep driving in the short term, but get it repaired soon: on many diesels, the warning eventually limits starting or engine power.

What causes code P2215?

The most common causes are: nOx element of the bank 2 sensor drifted low; fault in the measuring electronics of the sensor module; damaged lead between probe and sensor module.

Related codes

• P2202NOx Sensor Circuit Low (Bank 1 Sensor 1)
• P2213NOx Sensor Circuit (Bank 2)
• P2214NOx Sensor Circuit Range/Performance (Bank 2)
• P2216NOx Sensor Circuit High (Bank 2)
• P2217NOx Sensor Circuit Intermittent (Bank 2)

Sources

• law.cornell.edu: 13 CCR 1968.2
• gsi.ext.gm.com: 25OBDG04A
• gsi.ext.gm.com: 14OBDG04 Engine Diagnostics
• static.nhtsa.gov: MC 10074008 2280

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.