P0164 indicates the powertrain control module has detected a voltage above the expected range (typically above 1.0 volt) on the oxygen sensor signal circuit for Bank 2 Sensor 3. This sensor is typically mounted downstream of the catalytic converter and monitors catalyst efficiency. The high voltage reading usually signifies a short to voltage in the wiring or an internal sensor fault causing the signal line to remain high.
The wiring harness has chafed, melted, or rubbed through against the frame or exhaust, creating a short between the O2 sensor signal wire and a 12-volt power source or reference voltage.
The sensor's internal circuitry or heater element has shorted to the signal output, keeping the voltage artificially high regardless of exhaust oxygen content.
Moisture, salt, or physical damage in the electrical connector has bridged the signal pin to the heater power or another voltage source.
Silicone, coolant, or oil contamination on the sensor element can cause erratic high voltage readings, though this is less common for circuit-specific high voltage faults.
An internal fault in the PCM's input circuit is misreading the signal or generating a false high voltage, though this is a rare cause for this specific code.
Yes. Bank 2 Sensor 3 is a downstream oxygen sensor used only for catalyst monitoring; it does not control fuel mixture, so drivability and safety are typically unaffected, though the vehicle may not pass emissions testing.
Not necessarily. Circuit high-voltage codes are frequently caused by wiring shorts rather than sensor failure. Inspect the harness and connector for damage before replacing the sensor.
It is very unlikely. While a failed PCM input circuit could theoretically set this code, the vast majority of P0164 instances are resolved by repairing wiring or replacing the sensor. Verify the wiring thoroughly before considering PCM replacement.
Bank 2 refers to the engine bank opposite cylinder number 1; Sensor 3 is the third oxygen sensor on that bank, typically located downstream of the catalytic converter or secondary catalyst.