Emissions

P0052 — O2 Sensor Heater Control Circuit High (Bank 2, Sensor 1)

Severity: low Safe to drive

What P0052 means

The PCM switches the heater inside the upstream oxygen sensor on Bank 2 and monitors the voltage in that control circuit. The heater brings the sensor to operating temperature quickly so the engine can enter closed-loop fuel control soon after startup. P0052 sets when the circuit voltage reads higher than expected, for example from a short to voltage, a faulty heater element or a failing driver in the PCM.

Symptoms

  • Check Engine light on
  • Worse fuel economy
  • Rough or unstable idle
  • Hesitation when accelerating
  • Higher exhaust emissions
  • Sometimes no noticeable symptoms

Possible causes

  1. Failed heater element in the Bank 2 Sensor 1 oxygen sensor
  2. Damaged wiring or connector with the heater control wire shorted to power
  3. Corroded or damaged terminals at the sensor plug
  4. Blown fuse or faulty relay in the heater supply
  5. Faulty PCM driver or software issue (rare)

How to diagnose

  1. Scan codes and freeze frame data, and confirm which side of the engine is Bank 2 (the side without cylinder 1)
  2. Inspect the sensor wiring and connector for chafing, melting and corrosion
  3. Check the heater fuse and relay using the vehicle's wiring diagram
  4. Unplug the sensor and measure heater resistance against the specification
  5. Check the heater control wire for unwanted voltage with the circuit off, which points to a short to power
  6. Verify power and the control signal at the connector with the engine running
  7. If wiring and sensor are good, test the PCM and look for software updates

Common fixes

  • Replace the Bank 2 Sensor 1 oxygen sensor
  • Repair or replace damaged wiring and connectors
  • Replace the fuse or relay after finding what overloaded it
  • Reflash or replace the PCM if it is confirmed faulty

Questions and answers

What does P0052 mean?

The PCM found too high a voltage in the heater control circuit of the upstream oxygen sensor on Bank 2. The cause is usually the sensor itself or its wiring.

Can I drive with code P0052?

Yes, for a short time, since it does not threaten the engine. Fuel economy and emissions will get worse, so do not put the repair off for long.

What most often causes P0052?

A failed sensor heater or damaged wiring shorted to power is the most common cause. Check the fuse and PCM only after those.

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.