Haltech Wideband 02 Controller Manual - Manual (Page 10)

5. Calibration
There are two types of calibration for the HWC: free air calibration and sensor heater calibration.
Sensor heater calibration and first free air calibration is automatically performed the first time a
new sensor is used, while free air calibration should be executed frequently.
5.1 Free air calibration
To achieve maximum precision, the HWC and its sensor needs to be recalibrated frequently.
The sensor MUST be operated in free air for calibration.
If the wide-band sensor is installed in a vehicle, wait 6-8 hours after running the engine so that all
exhaust gas is dissipated from the exhaust tract of the vehicle. Better yet, disengage the oxygen
sensor and expose the sensor to air (away from the exhaust) for calibration purposes:
1. Connect
the HWC to 12V from the vehicle and switch it on.
2. After the sensor has warmed up, either press the pushbutton or connect the calibration wire
to ground for a brief period.
3. After the calibration is complete, switch the HWC off and wait for 30 seconds before you start
the car.
If a LED indicator is connected to the calibration wire, it will be off during free air calibration.
5.2 Sensor heater calibration
If you change the sensor – either with a replacement sensor or a new type of sensor --, the
heater circuit of the HWC needs to be recalibrated as well. (See steps in chapter 4 'First Time
Use'). The heater calibration data in the HWC will be reset when the device is operated from 12V
without a sensor connected for at least 5 seconds. You can force a reset by doing this, and then
recalibrate by turning the unit off, reconnecting the sensor, and turning the unit on.
After the sensor is warmed up the meter automatically calibrates the sensor heater controller to
the particular sensor. During this 20-second period the HWC collects and calculates sensor-
specific data required to quickly reach operating temperature in the future.
Note: When using the Bosch Sensors the HWC may perform multiple calibration passes.
This is normal and need not cause concern. When it completes, the HWC also will perform
a free air calibration. Make sure the sensor is operating in free air for the heater and free
air calibration.
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