Wideband Controller for BOSCH 4.9


The LDperformance Wideband controller uses the Bosch LSU ADV or 4.9 sensor and is based on the original CJ125 chip which provides reliable and fast AFR measurement. Suitable for use with most Standalone ECUs.

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  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
  6. Smart warmup feature ensures long life of the lambda sensor.

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

Wiring diagram


  1. Good visibility, fast response screen
  2. 0-5V Signal input or LDperformance digital signal (automatically recognised)
  3. Big digit size – 1 inch, instead of the common 0.56".
  4. Size: 78mm x 40mm

Internal Hardware

  1.  <0.5% accurate voltage reference
  2. Separate voltage reference from display supply
  3. 10bit ADC with improved resolution using successive approximation algorithm
  4. Hardware and software noise filter

How to use

  1. Connect the 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.

0-1V Narrowband output

It is possible to reconfigure the 0-5V wideband output to show 0-1V Narrowband signal. To do this connect the wire to ground and turn on the controller for 3 seconds. To switch back to 0-5V output repeat the same precedure.

Smart sensor warmup

  • If the wideband kit is going to be permanently installed in a vehicle, the Smart warmup function must be activated.
  • It prolongs the life of the sensor by avoiding rapid heat up during the initial water-condensation phase.
  • To activate it, connect the digital output wire to ground and power up the controller for 3 seconds. (Repeating the same procedure will disable the function.)
  • Many wideband sensors fail prematurely because rarely aftermarket controller manufacturers pay attention to the sensor warmup procedure when the engine is cold. What usually happens is condensed water from the exhaust hits the hot sensor and the shock damages the sensing element.
  • The LDperformance Smart warmup process monitors the sensor temperature and applies full sensor warmup only after the exhaust is heated sufficiently by the engine. This means that when exhaust is cold the sensor will become fully operational in 2-7minutes after engine is started.
  • This feature is used by all OEM car manufacturers but neglected by the aftermarket.
  • Smart warmup feature is disabled by default.

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.

LDperformance wideband is the only aftermarket controller that uses Smart warmup function to avoid premature failure of the lambda sensor.

Sensor Calibration

No user calibration is required for proper operation.

Reconfigure controller to be used with 4.9 sensor instead of ADV

It is possible to reconfigure the controller for use with 4.9 sensor.

  1. Connect both 0-5V output and digital output wire to ground.
  2. Turn on controller for 3 seconds and turn off.
  3. Confirm the setting is changed by checking the initial reading on the display when initialising - 4.9 or ADV.
  4. Repeat the same process to switch back.

How do I know if Smart warmup is enabled?

The display will show " --- " when it waits for the engine to heat up the exhaust. If it shows " H-- " instead, then Smart warmup is not enabled and it will heat up the sensor quickly.

How do I know if the controller is set up for 4.9 or ADV sensor?

The display will show "4.9" or "ADU" briefly when powering up.

Additionaly the analogue output shows 10-20, 10-20 etc... while heating up the sensor. That means its for ADV. If it shows 10-15, 10-15... its for 4.9 sensor.


The wideband controller includes all necessary cables:

6pin cable from lambda sensor to controller

4 pin cable for power and signals


Additional information


Full kit, Wideband controller+AFR display, Wideband Controller+Bosch LSU 4.9, Wideband Controller only, AFR Display only