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

P0144

O2 Sensor Circuit Low Voltage (Bank 1 Sensor 3)

The ECU detects an abnormally low voltage from the third O2 sensor on bank 1. Indicates persistently lean exhaust, an open sensor or wiring shorted to ground.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 44

Possible causes

  • Lean exhaust (vacuum leak, low fuel pressure) high
  • Signal wire shorted to ground medium
  • O2 sensor failed medium

Symptoms

  • Check engine light on
  • Increased fuel consumption
  • Possible rough idle or hesitation
  • Failed emissions test

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 80–350 €
  • Estimated time: 0.3–1.5 h
  • Component: oxygen sensor b1s3
  • Component: oxygen sensor wiring
  • 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