Description
(1) ON/OFF oxygen sensor
"a" 4-way green or blue connector (*)
2 types of ON/OFF oxygen sensor (*)
- Upstream oxygen sensor ON/OFF (green 4-way connector)
- Downstream oxygen sensor ON/OFF (4-way blue connector)
Role
The ON/OFF oxygen sensor determines the oxygen content of the exhaust gas and permits checking of the operation of the catalytic converter and resetting of the mixture following a drift of the injection system and of the catalytic converter
Function
The oxygen contained in the exhaust gas is compared with the oxygen contained in the ON/OFF oxygen sensor sampled from the ambient air to deduce a mixture value
If the difference between the oxygen contained in the exhaust gas and the oxygen contained in the ON/OFF oxygen sensor is significant the mixture will be "rich", if the difference is slight the mixture will be "lean"
The ON/OFF oxygen sensor (1) compares the composition of the mixture injected with the stoichiometric dosage (lambda = 1) to deduce an output voltage
NoteLambda signal ratio = weight of air admitted/theoretical air weight
Electrical features
"b" rich area
"c" poor area
The "rich" or "lean" mixture information is given by 0,1 to 0,9 V voltages
Lean mixture = approximately 0,1 V (Lambda higher than 1)
Rich mixture = approximately 0,9 V (Lambda lower than 1)
The engine management ECU regulates the richness by varying the injection time to get as close as possible to the stoichiometric dosage (lambda signal = 1)
The ON/OFF oxygen sensor contains an internal heating device which allows it to reach its operating temperature quickly (higher than 300° C)
| channel number | allocation of channels of connector |
|---|---|
| 1 | positive power supply (12 Volts): oxygen sensor heating ON/OFF |
| 2 | ON/OFF oxygen sensor heating control |
| 3 | ON/OFF oxygen sensor negative signal |
| 4 | ON/OFF oxygen sensor positive signal |
Programming - initialisation
Programming is necessary if the component is replaced