P2233 indicates a short circuit in the heater circuit of the oxygen sensor (Bank 1, Sensor 3). This typically means the sensor's internal heater element or its wiring has a short to voltage or ground, causing the PCM to detect an abnormal current draw.
The most common cause. The sensor's heater element can short internally, drawing excessive current and triggering the code.
Wires can chafe against the exhaust or other components, causing a short to ground or to power. This is especially common on older vehicles or after repairs.
A poor connection or internal short within the connector can mimic a sensor failure. Inspect for signs of heat damage or moisture intrusion.
The PCM's internal heater driver circuit can fail shorted, but this is uncommon. Only consider after thoroughly testing the sensor and wiring.
Yes, usually the vehicle will still run, but the oxygen sensor may not heat properly, leading to increased emissions and possible fuel trim issues. It is best to diagnose and repair the problem soon to avoid failing an emissions test or causing catalytic converter damage.
No. While the sensor itself is the most common cause, wiring or connector issues can also produce this code. Proper diagnosis is essential to avoid replacing a good sensor.
Rarely. The PCM is often blamed for P2233, but it is almost never the cause. Only consider PCM replacement after thoroughly testing the sensor, wiring, and connectors. In most cases, the fix is a new oxygen sensor or a wiring repair.
Bank 1 refers to the side of the engine containing cylinder #1. Sensor 3 is the third oxygen sensor in the exhaust stream on that bank, typically the downstream (post-catalyst) sensor. On many vehicles, there are only two sensors per bank, so Sensor 3 may be a secondary downstream sensor on some applications.