#
HO2S HEATER CONTROL OPERATION [AJ]

BME014000000T72

## HO2S (Front) Heater

• HO2S (front) heater is controlled by the PCM as follows:

  - PCM runs the heater control with a 0% duty signal when the following conditions are met.

  • The ignition switch is ON with the engine stopped
  • Engine speed is above 4,000 rpm
  • Charging efficiency is above 75%

  - PCM runs the heater control with a 30% duty signal when the following conditions are met.

  • When starting
  • Engine speed below 4,000 rpm
  • Battery voltage above 16 V
  • Engine coolant temperature or intake air temperature is below 5 °C {41 °F}
  • ECT sensor, TP sensor or IAT sensor has a malfunction

  - PCM runs the heater control with a 100% duty signal when following conditions are met.

  • At idle for a specified period after the engine is started when engine coolant temperature is 0-40 °C {32-104 °F} and above 70 °C {158 °F}.

## HO2S (Rear) Heater (European (L.H.D.) Specs.)

• PCM turns HO2S (Rear) heater ON when for specified period when following conditions are met.

  - Engine speed below 4,000 rpm
  - Charging efficiency below 75%