The powertrain control module detects that the reference voltage circuit for the oxygen sensor on bank 2, sensor 1 is lower than expected.
The sensor's internal reference circuit can fail, causing the voltage to drop below the required level.
Loose, broken, or corroded wires or connector pins can interrupt the reference voltage supply.
Insufficient grounding or high resistance in the circuit can lower the measured voltage.
A blown fuse or intermittent power to the sensor circuit can result in low reference voltage.
The control module's driver circuit for the sensor reference voltage can malfunction, though this is less common.
Very high or low temperatures can affect sensor electronics, but usually do not cause a persistent low reference voltage code.
No. The PCM is rarely the cause; most often the fault is a bad sensor, wiring, or grounding issue.
Yes. A failed reference voltage circuit inside the sensor itself is a common cause of P2249.
Driving is usually possible for a short time, but prolonged operation may reduce fuel efficiency and increase emissions.
Repair or replace only the damaged wiring or connector; if the sensor itself is faulty, replace the sensor.