P2249: O2 Sensor Reference Voltage Circuit Low (Bank 2 Sensor 1)
Standardized SAE J2012 code · P22xx — Fuel & air metering and auxiliary emission controls
What does P2249 mean?
Bank 2 counterpart to P2245. The reference voltage on bank 2, sensor 1 is below the lower threshold — typically a short to ground or failed ECU output.
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Common causes
- High Reference line shorted to ground
- Low ECU reference output failed
- Low Connector pins corroded - high contact resistance
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of P2249 on the same make and model first.
P2249 in the community
Ask about P2249No one has posted about P2249 yet
Share your vehicle, the tool you used and what you tested — the first thread helps everyone who searches for this code.
Describe your P2249 problemRelated codes
- P2245 O2 Sensor Reference Voltage Circuit Low (Bank 1 Sensor 1)
- P2248 O2 Sensor Reference Voltage Circuit Range/Performance (Bank 2 Sensor 1)
- P2250 O2 Sensor Reference Voltage Circuit High (Bank 2 Sensor 1)
- P22B0 O2 Sensor Reference Voltage Circuit Low (Bank 1 Sensor 2)
- P22BD O2 Sensor Reference Voltage Circuit Low (Bank 2 Sensor 2)