P0138
Systeem
Powertrain (Emissions)
Scanner vereist
Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)

Understand P0138, common causes, and the right FOXWELL scanner to diagnose it.

Downstream O2 sensor bank 1 reading high — often failed sensor after catalytic converter or rich running condition.

Veelvoorkomende symptomen

  • Check engine light
  • Failed emissions
  • May appear with P0420

Typische oorzaken

  • Failed downstream O2 sensor
  • Rich fuel mixture
  • Exhaust leak
  • Contaminated sensor from oil/coolant

Welke scanner heb je nodig?

Enhanced OBD2 scanner (live data graphs, freeze frame, battery voltage test)

Gebruik live data en freeze frame voordat je onderdelen vervangt. ABS-, SRS- en U-codes vereisen meestal een full-system scanner.

Diagnosetips

  • Leg freeze frame vast wanneer de code voor het eerst verschijnt
  • Wis de code pas na het oplossen van de oorzaak
  • Controleer op gerelateerde pending codes
  • Controleer of accuspanning boven 12,4 V is voordat je sensoren suspecteert

Aanbevolen FOXWELL scanners

Veelgestelde vragen

Can I diagnose P0138 with a basic code reader?
P0138 may set in the engine module, but related diagnostics often benefit from an enhanced or full-system scanner with live data and freeze frame.
Is it safe to drive with P0138?
It depends on the code and symptoms. Flashing check engine lights and misfire codes should be addressed immediately. Consult a professional if unsure.