Emissions

P0162 — O2 Sensor Circuit High Voltage (Bank 2 Sensor 3)

Severity: low Safe to drive

What P0162 means

The engine control unit monitors the oxygen sensor on the second cylinder bank, located downstream of the catalytic converter (Bank 2, Sensor 3). A healthy sensor produces a signal within a defined voltage range that reflects the oxygen left in the exhaust. P0162 sets when the circuit voltage is too high or out of range, so the ECU cannot rely on the sensor to judge catalyst performance.

Symptoms

  • Check Engine light on
  • Slightly higher fuel consumption
  • Unstable idle (uncommon)
  • Increased exhaust emissions
  • Failed emissions test
  • Additional codes for the catalyst or fuel trim

Possible causes

  1. Failed Bank 2 Sensor 3 oxygen sensor
  2. Damaged wiring or corroded connector in the sensor circuit
  3. Signal wire shorted to voltage
  4. Wiring melted or chafed near the exhaust
  5. Exhaust leak near the sensor
  6. Rarely, a faulty ECU input channel

How to diagnose

  1. Read all codes and freeze frame data, clear the code and see whether it returns.
  2. Confirm which sensor is Bank 2 Sensor 3 using the wiring diagram for your vehicle.
  3. Inspect the harness and connector for melting, chafing, moisture and corrosion.
  4. Watch live sensor data: voltage, response to changing engine load and heater operation.
  5. Unplug the connector and test the signal wire for a short to voltage or an open circuit.
  6. Check sensor power and ground supply and the heater resistance against specification.
  7. Look for exhaust leaks upstream of the sensor.
  8. Review Bank 2 fuel trims to rule out a mixture problem.

Common fixes

  • Replace the Bank 2 Sensor 3 oxygen sensor
  • Repair the wiring and replace a damaged connector
  • Fix the exhaust leak
  • Correct any mixture problem found
  • Repair or replace the ECU as a last resort

Questions and answers

Can I drive with P0162?

Usually yes, for a short time, as it rarely harms the engine. Fix it soon anyway to avoid higher emissions and possible extra fuel use.

What does Bank 2 Sensor 3 mean?

Bank 2 is the cylinder bank that does not contain cylinder 1. Sensor 3 is the third oxygen sensor in the exhaust, normally downstream of the catalyst.

Do I always need a new sensor?

No. Check the wiring, connector and exhaust leaks first, because they are often the real cause rather than the sensor.

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.