Derbi Rambla 250 Manual page 183

Injection
11
The lambda probe or oxygen sensor is a sensor which provides information about the oxygen content
in the exhaust fumes. The signal generated is not of the proportional but of the ON/OFF type, i.e. whether
there is oxygen or not. The probe is positioned on the exhaust manifold before the catalytic converter
in an area where the gas temperature is always high. The temperature at which the probe works is at
least 350°C at 600°C and it has a reaction time of just 50 milliseconds. The signal generated passes
from a high value to a low one with a mixture with lambda =1. Since the probe only works at high
temperatures, it has an electric preheating element inside, controlled by the control unit, to make it start
operating quickly.
Specific tooling
AP8181059 Control unit interface wiring
Check that the 20A main fuse No. 2 and the injection load 15A No. 4 fuse are in good conditions.
Check there is voltage between pins 21 and 26 of
the interface wiring for around two seconds,
switching to "ON"
With the engine cold, check the resistance of the
lambda probe heater between pin 21 of the inter-
face wiring and the Red-Brown cable of the injec-
tion load remote control base, with both the control
unit and the remote control disconnected.
Resistance of the heater at about 20° = 9 Ohm ±
20%
Specification
Electric fan remote control
Desc./Quantity
INJEC - 183