P2249 code meaning
O2 Sensor Reference Voltage Circuit Low (Bank 2 Sensor 1)
Powertrain system Generic code P22xx codes Check engine light
What P2249 means
P2249 indicates that the reference voltage circuit of the front air-fuel sensor on bank 2 is pulled too low, most often by a grounded wire in the harness or a fault inside the sensor. The only public manufacturer criteria come from GM's tables for the Saturn Vue 3.5 V6 (L66, 2004-05), a Honda-built engine: after more than 85 s of running with the sensor heater active and the element signal at 3.2-4.6 V, a pump-cell circuit voltage under 1.5 V for half a second stores the code and lights the MIL in that drive cycle. The same table uses P2245 for bank 1. Ford, VW and GM's Bosch-equipped V6 tables do not list P2249. CARB requires circuit faults of fuel-control sensors to be detected. P2247 is the open line, P2250 high, P2255 the low fault of the ground line.
P2249 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2249
- Check engine light
- Higher fuel consumption from open-loop fuelling on bank 2
- Possible failed emissions test
Common causes of P2249
- Most likelyReference voltage wire shorted to ground on the bank 2 sensor harness
- PossibleInternal short in the bank 2 air-fuel sensor
- Less likelyFault in the sensor interface of the ECM
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor bank2 sensor1Oxygen sensor wiringECM
What each part of P2249 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 2 | Area: fuel and air metering (injector circuit). |
| 49 | The exact fault in that area. |
What to do next
- Note P2249 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2249
What does P2249 mean?
P2249 means "O2 Sensor Reference Voltage Circuit Low (Bank 2 Sensor 1)". P2249 indicates that the reference voltage circuit of the front air-fuel sensor on bank 2 is pulled too low, most often by a grounded wire in the harness or a fault inside the sensor. It is a generic code, so it means the same on every make.
Is it safe to drive with P2249?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P2249 fail an emissions test?
Yes, it can. P2249 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2249 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2249 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.