LCU-ONE CAN connected to MyChron4
User Manual 
Release 1.04
 
0Chapter 1 – LCU-ONE 
LCU-ONE is a lambda controller unit for wide band BOSCH LSU 4.9 lambda probe; it 
fits petrol (2 and 4 strokes), diesel and methane engines as well as alcohol based fuel 
engines. It is intended to check lambda probe proper working as well as to transmit the 
Air/fuel ratio values providing MyChron4 with lambda values through the CAN bus. 
Lambda value is defined as: LAMBDA= (A/F)/(A /F) Stoichiometric 
where: 
A = incoming parts of air; 
F= parts of petrol the carburettor introduces in the engine; 
A/F Stoichiometric = parts of air needed to burn Stoichiometric F; 
Speaking about gasoline, for example, it needs 14,57 parts of air to completely burn a 
part of gasoline, obtaining Lambda value = 1 read by the probe. 
LCU-ONE controller can detect lambda values in a range of 0.65 to 1.6 (free air). 
It is reminded that LAMBDA value lower than 1 means a rich mixture, while 
LAMBDA value higher than 1 means a lean mixture. 
Wide band Lambda probes need to be heated to work properly and not poison with 
exhaust gas; LCU-ONE controller precisely manages the probe heater so to keep 
temperature value in the optimum working range. 
Lambda probe used with LCU-ONE controller becomes very hot (around 700-800 °C, 
1292-1472 °F) during its working period, it is thereby necessary AVOIDING: 
•touching it. 
•placing it in contact with inflammable stuff or fuel. 
Please note: 
disrespect of these precautions can cause shocks, burnings or explosions. 
71.1 – Part Numbers 
LCU-ONE CAN part numbers are: 
•Controller LCU-ONE (Complete kit with Lambda probe) X08LCU03K0; 
•BOSCH LSU 4.9 Lambda probe X05LSU490.
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