This code indicates the engine computer has detected an electrical short between the oxygen sensor's signal circuit and its internal heater circuit for the upstream O2 sensor on bank 2. Bank 2 is the side of the engine that does not contain cylinder #1, and sensor 1 is the upstream (pre-catalytic converter) sensor. The fault is almost always in the sensor itself or its wiring, not the engine computer.
Internal shorting between the heater and signal elements inside the sensor is the most common cause, often due to age, contamination, or thermal damage.
The signal and heater wires can short together where the harness routes near hot exhaust components or sharp chassis edges.
Corroded, bent, or pushed-back terminals in the sensor or harness connector can bridge the signal and heater circuits.
A sensor with the wrong pin configuration for this vehicle can internally cross the signal and heater circuits.
Extremely rare; a failed driver circuit inside the PCM could theoretically cause this code, but it should only be considered after the sensor, wiring, and connector are fully verified good.
Short trips are usually fine, but the engine may run less efficiently and emissions may rise. Prolonged driving can affect catalyst health and will typically fail an emissions inspection.
Almost never. Shops and online sources sometimes suggest replacing the PCM, but the real cause is almost always the sensor, wiring, or connector. The PCM should be the last component considered and only after exhaustive testing.
If the sensor internally shorts the signal and heater elements, yes. However, confirm the wiring and connector are intact first, because a harness short can set the same code and ruin a new sensor if not repaired.
It is the oxygen sensor mounted in the exhaust manifold or close-coupled pipe on the side of the engine opposite cylinder #1, before the catalytic converter.