On-Board Diagnosis System II - Volkswagen Technical Site

System Components (Gasoline Engine)
Lambda control
OBD II checks with regard to
lambda control:
● response/aging characteristics
● voltage applied to lambda probes
● probe heater
Lambda probe aging diagnosis
Aging or poisoning can adversely affect the
response of a lambda probe. A deterioration can
become noticeable by an increase in probe
reaction time (period duration) or a shift in the
probe voltage curve (probe shift). Both situations
lead to a reduction in the λ window and to
poorer exhaust gas conversion in the catalytic
converter.
A change in reaction time can be acquired,
stored and displayed but cannot be compensated
for.
In the Motronic M5.9.2, the shift in the voltage
curve is corrected within a defined framework by
means of a second closed control loop
(adaption).
Testing the reaction time of the primary catalytic converter probe
Primary catalytic
converter probe
OK
Primary catalytic
converter probe
NOK
175_049 175_050
U
U
U
U
t
t
t
t
Primary catalytic
converter
Secondary
catalytic converter
Primary catalytic
converter
Secondary
catalytic converter
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