Heater Control and Sensor Calibration

Heater Control

During engine start-up, condensation forms in the exhaust which may damage the sensor.  It is recommended to only start heating the LSU sensor after the engine is running and the moisture content in the exhaust has evaporated. The ECU has settings to prevent this damage;  “Heater RPM Lockout” and “Heater Post Start Lockout”

Typical Values:    

Heater RPM Lockout = 500 RPM    

Heater Post Start Lockout = 4.0 Sec

Calibration 

The sensor is calibrated automatically by the ECU on power up. During the calibration process two important pieces of data are read:

• The optimal Nernst Cell Temperature which is used for sensor heater control. The ELC applies duty cycle and a PID routine to maintain a constant and accurate heater temperature which results in a very stable and accurate Lambda value. 
• The Pump Current that corresponds to a Lambda reading of 1.000 Lambda.

NOTE: A Free-Air Calibration is NOT required on the LSU4.9. The sensor uses a reference pump current instead of reference air. The big advantage with this is that the reference is a calibrated electrical signal and remains constant.