OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

P0141

O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 2)

The heating element inside the downstream oxygen sensor on bank 1 is open-circuit, drawing no current, or drawing too much. Without heater, the sensor takes much longer to reach operating temperature, delaying catalyst diagnosis.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 41

Possible causes

  • Heater element open-circuit high
  • Heater fuse blown medium

Symptoms

  • Check engine light on after several drive cycles
  • Slightly increased fuel consumption during cold start
  • Delayed entry into closed-loop fuel control
  • Failed emissions inspection (lambda readiness)

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 60–250 €
  • Estimated time: 0.3–1.5 h
  • Component: oxygen sensor downstream
  • Component: oxygen sensor heater relay
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication