ECU Setup
Analogue wideband lambda sensor
Wire and calibrate an external 0–5 V wideband lambda controller using the analogue input scaling in SXTune.
This page is for an external analogue 0–5 V wideband controller. For an ECU with the SCS internal wideband controller, use Internal wideband & closed-loop lambda.
Sensor installation
Choose a mounting position that reduces the chance of condensation collecting on the sensing element. The previous guide recommends arranging the sensor so water cannot run into the protective shroud. Avoid fully heating a cold sensor before a wet/cold exhaust is started where possible.
Wiring and output configuration
If the ECU is being used to control the external wideband heater, configure the correct low-side output for the lambda heater drive according to the ECU pinout. The exact output pin varies by ECU.
Calibrate the 0–5 V signal
- Open Sensor Setup → Analogue Inputs Setup.
- Obtain the controller manufacturer's lambda/voltage transfer data.
- Enter the lambda values corresponding to the minimum and maximum output voltages in the analogue wideband scaling fields.
- Save the calibration and compare the SXTune lambda value with the controller/display or independent analyser.
The old guide used approximately λ0.68 at 0 V and λ1.36 at 5 V only as a typical example. Use the actual controller datasheet rather than copying those numbers.
