Powertrain
generic / SAE
P2249
O2 Sensor Reference Voltage Circuit Low (Bank 2 Sensor 1)
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.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number2 / 49
Possible causes
- Reference line shorted to ground high
- ECU reference output failed low
- Connector pins corroded - high contact resistance low
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 120–500 €
- Estimated time: 0.5–2 h
- Component: oxygen sensor upstream b2
- Component: oxygen sensor wiring
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012