Emissions

P0144 — O2 Sensor Circuit High Voltage (Bank 1 Sensor 3)

Severity: low Safe to drive

What P0144 means

The PCM detected that the signal from the Bank 1 Sensor 3 oxygen sensor stays above the expected voltage. This sensor sits in the exhaust after the main catalytic converter (or after a second converter on some vehicles) and helps monitor converter performance. A short to voltage in the wiring or a failed sensor can pin the signal high.

Symptoms

  • Check engine light on
  • Often no noticeable driveability change
  • Possible slight increase in fuel consumption
  • Failed emissions inspection
  • Occasionally an unsteady idle

Possible causes

  1. Failed Bank 1 Sensor 3 oxygen sensor
  2. Signal wire shorted to voltage
  3. Damaged wiring harness or corroded, loose connector
  4. Exhaust leak near the sensor
  5. Open sensor ground circuit
  6. Rarely, a PCM input circuit fault or software issue

How to diagnose

  1. Scan for codes and freeze frame data, and note any other O2 sensor or catalyst codes
  2. Inspect the sensor harness and connector for chafing, melting, corrosion or contact with the exhaust
  3. Check for exhaust leaks at and ahead of the sensor
  4. Watch the sensor voltage in live data with the engine warm and while changing throttle
  5. Unplug the sensor: if the circuit voltage stays high, look for a short to power in the wiring
  6. Test reference voltage, ground and circuit resistance with a multimeter using the wiring diagram
  7. Review fuel trims to rule out a mixture problem

Common fixes

  • Repair the wiring or replace the connector
  • Replace the Bank 1 Sensor 3 oxygen sensor
  • Fix any exhaust leak
  • Update the PCM software if the manufacturer has a bulletin
  • In rare cases, repair or replace the PCM

Questions and answers

What does P0144 mean?

It means high voltage in the oxygen sensor circuit for Bank 1 Sensor 3, usually the sensor behind the catalytic converter. The sensor or its wiring is the most common cause.

Can I drive with a P0144 code?

Usually yes for a short time. Still, don't put off diagnosis, so you don't fail an emissions test or miss another problem.

How do I fix P0144?

Start by inspecting the wiring and connector and checking for exhaust leaks, then test the sensor signal. Wiring repair or sensor replacement fixes most cases.

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.