P2A00 Code O2 Sensor Circuit Range/performance–Bank 1 Sensor 1

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P2a00 code code displaying on an OBD-2 diagnostic tool

Table of Contents

What does P2A00 code mean?

The P2A00 code means that the O2 sensor reads a voltage outside the normal range. A faulty oxygen sensor causes this. it’s more likely that you have another problem with your vehicle. The most common cause of this code is an electrical short or wiring issue in the engine bay, which will require further inspection and repair work to fix.


  • The check engine light is on.
  • Your engine can stall at idle.
  • The engine may run rough, roughly, or roughly at high and low speeds.


  • Ignition misfiring
  • The engine running too lean or rich (too much fuel and not enough air)
  • Incorrect valve timing, which can cause the engine to run at an improper RPM for its load conditions
  • Fuel injector issues that cause abnormal amounts of fuel flow into your engine’s cylinders
  • Crank sensor issues with internal wear that prevent proper timing signals from reaching your vehicle’s ECM

Repair tips

  • Check the sensor and wiring harness for damage.
  • Check the sensor for loose connections.
  • Check the ECU for damage or corrosion.
  • Check the connector for damage or corrosion.
  • Check the sensor for damage or corrosion (if you can’t find it, use a voltmeter to check if there’s a voltage at that location).

If you have access to an ohmmeter, check the continuity between pins 1 and 2 of your O2 sensor when it is cold, then again when hot – both should give similar readings (less than 1 ohm). If not, replace your O2 sensor!