P2247 indicates that the powertrain control module (PCM) has detected an open circuit in the reference voltage line for the oxygen sensor on Bank 2, Sensor 1. This reference voltage is typically 0.45V for narrowband or 5V for wideband sensors, and an open circuit prevents the sensor from operating correctly, often causing a rich or lean fuel trim condition.
The most common cause is a broken, chafed, or corroded wire in the reference voltage circuit between the PCM and the O2 sensor connector.
Corrosion, bent pins, or a loose connection at the sensor harness can create an open circuit.
The sensor itself may have an internal open circuit in the reference voltage path, requiring replacement.
A blown fuse for the O2 sensor circuit or a damaged ground can interrupt the reference voltage supply.
In very rare cases, a fault within the PCM can cause loss of reference voltage output; this should only be considered after all other possibilities are exhausted.
You may be able to drive short distances, but the engine may run poorly, fuel economy will suffer, and emissions will increase. It's best to diagnose and repair promptly.
Not necessarily. The code points to an open circuit, which is often a wiring or connector issue. Always test the circuit before replacing the sensor to avoid unnecessary parts replacement.
No. PCM failure is very rare for this code. The vast majority of cases are caused by wiring, connector, or sensor issues. Only consider PCM after thorough diagnosis.
For narrowband O2 sensors, the reference voltage is typically 0.45V. For wideband (air-fuel ratio) sensors, it is usually 5V. Check your vehicle's service manual for the exact specification.