Wideband Controller for 4.9 or 4.2


The LDperformance Wideband controller uses the Bosch LSU 4.9 or 4.2 lambda sensor. Based on the original CJ125 chip it provides reliable and fast AFR measurement. Suitable for use with most Standalone ECUs.


Product Description

Bosch LSU ADV lambda sensor

Wideband controllers for Bosch LSU 4.9 and 4.2 are available. Choose from the list above!

We do not offer 4.2 or 4.9 lambda sensors any more but our wideband controllers are still available. Great choice if your car already has a 4.2 lambda sensor fitted.

Full wideband kits are available here using the latest Bosch lambda sensor - LSU ADV!


  1. 7.4 AFR to 25.5 measurement range
  2. Accuracy <0.1AFR
  3. Simple to install and operate
  4. 0-5V Analogue Output
  5. 100% Accurate digital signal between Controller and Display
Technical details
  1. Uses PID algorithm to control probe temperature
  2. Initial Heat up of sensor designed according to Bosch specification
  3. Immediate sensor turn-off under fault condition to protect sensor
  4. Aluminium enclosure + 3D Printed plastic
Wiring diagram



How to use

  1. Connect the correct Bosch oxygen sensor using the extension lead to the Controller
  2. Connect 12V and GND to the corresponding terminals of the Controller and AFR display
  3. Connect one of the Controller signal wires to the AFR Display input
0-5V Analogue output

The analogue 0-5V output corresponds to 7.35AFR to 22.39AFR. To convert from voltage to AFR use the formula: V*15.04/5+7.35. The output is compatible with many Wideband AFR displays as well as the LDperformance AFR display.
During the initial heat-up phase of the sensor, the output will toggle 10AFR, 20AFR. This is done to verify the accuracy of the signal and the gauge.

Digital output

The Digital Output works only with the LDperformance AFR display and is used to 100% accurately display AFR on the gauge.
The LDperformance AFR display has a single input which can automatically detect if analogue or digital signal is connected.

Why LDperformance Wideband

By integrating the CJ125 chip which is specifically designed by Bosch for their lambda sensors, faster response times and more accurate readings can be achieved. The kit also uses the best and newest lambda sensor technology LSU ADV which is the successor of LSU 4.9 

Sensor Calibration

No user calibration is required for proper operation. 



Wideband controller for 4.2, Wideband Controller for 4.9