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O2 Sensor Heater Relay Control

O2 SENSOR HEATER RELAY CONTROL (M3.x and earlier Systems)

Early engine control Systems (M3.x and previous) provide a ground for the Oxygen Sensor Heater Relay providing power to the heating elements in the sensor(s). The control of the relay is activated after a pre-determined programmed duration of time shortly after engine start up. At VL throttle angle the Engine Control Module switches the relay off