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OBD-II · Engine and powertrain (P)

P0052

Oxygen sensor heater control circuit high bank 2 sensor 1

What it means

The heater control circuit of the upstream (before the catalytic converter) lambda sensor on bank 2 reads higher than expected, usually from a short to battery voltage or a shorted heater. Confirm bank 2's location in the engine's service information.

Symptoms

  • engine warning light
  • slightly higher fuel consumption and emissions after a cold start
  • usually no change in how the car drives

Likely causes, most likely first

Likely causes, most likely first
No.Cause
01control wire short to battery voltage
02internally shorted heater element
03water or damage in the connector
04ECU driver fault

What to check, step by step

  1. 01Check the ECU control wire for a short to battery voltage
  2. 02Measure the heater resistance: an internally shorted heater draws too much current
  3. 03Inspect the connector for water or melted pins
  4. 04Replace the sensor if the heater is out of spec; repair wiring otherwise