2003 Mercury Grand Marquis OBD2 Code P0141 O2 Sensor Heater Circuit

What Does P0141 Code Mean?

Fault Code Definition

The Catalyst Monitoring Oxygen Sensor evaluates the rear most Catalytic Converter's emissions-reducing capability. Code P0141 is set when the Rear Oxygen Sensor does not show signal activity indicative of closed loop fuel system operation within the required time.

P0141 Symptoms

  • Check Engine Light will illuminate
  • In many cases, no abnormal symptoms may be noticed
  • In some cases, the vehicle will fail an Emissions Test
  • In many cases, the NOx emissions will be elevated

Common Problems That Trigger the P0141 Code

  • Defective Rear Most Oxygen Sensor
  • Faulty Rear Most Oxygen Sensor wiring or connections

Common Misdiagnoses

  • Oxygen Sensor Sensor is replaced when the problem is a defective Catalytic Converter
  • Oxygen Sensor is replaced when the problem is faulty sensor wiring or connections
  • Oxygen Sensor is replaced when the problem is an exhaust leak before the Rear Oxygen Sensor

OBD II Trouble Codes