Emissions

P0164 — O2 Sensor Circuit High Voltage (Bank 2 Sensor 3)

Severity: low Safe to drive

What P0164 means

The engine control module constantly monitors the signal from the Bank 2 Sensor 3 oxygen sensor, typically an extra sensor located after the catalytic converter that helps judge converter performance. P0164 is set when the circuit voltage stays above the expected range. Common causes are a failed sensor, a short to voltage in the wiring, or, rarely, a fault in the control module.

Symptoms

  • Check engine light on
  • Rough idle or hesitation under acceleration (not always)
  • Reduced fuel economy
  • Higher emissions or a failed emissions test
  • Unstable idle in some cases

Possible causes

  1. Failed Bank 2 Sensor 3 oxygen sensor
  2. Damaged wiring or corroded connector at the sensor
  3. Signal wire shorted to voltage
  4. Exhaust leak near the sensor
  5. Sensor contamination or damage affecting its signal
  6. Sensor circuit fault in the PCM (rare)

How to diagnose

  1. Scan for codes and freeze frame data, and note any other O2 sensor or fuel trim codes
  2. Confirm which sensor is Bank 2 Sensor 3 using a diagram for your vehicle
  3. Inspect the sensor, harness and connector for melting, chafing, moisture or corrosion
  4. Check the exhaust for leaks near the sensor
  5. View live sensor voltage and heater status with a scan tool
  6. Review fuel trim values for upstream mixture problems
  7. Unplug the connector and test power, ground and signal wire for a short to voltage
  8. If the wiring is good, compare the signal to specs and replace the sensor

Common fixes

  • Replace the Bank 2 Sensor 3 oxygen sensor
  • Repair or replace damaged wiring and connectors
  • Fix any exhaust leak near the sensor
  • Reflash or replace the PCM (very rare, only after ruling out everything else)

Questions and answers

What does P0164 mean?

The PCM detected abnormally high voltage in the Bank 2 Sensor 3 oxygen sensor circuit. The cause is most often the sensor itself or its wiring.

Can I drive with code P0164?

Usually yes for a short time. Fuel economy and emissions may suffer, so get it diagnosed soon.

What should I check first?

Inspect the sensor wiring and connector, look for exhaust leaks, and read the sensor voltage with a scan tool. That often reveals the cause.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.