Skoda Octavia Workshop Manual page 29

OCTAVIA
Display Readout on V.A.G
block 1552
3 constant between
0.40 and 0.50 V
constant 0.00 V
Notes on display block 3:
♦ The voltage signal „rich mixture (low level of residual
oxygen)" is at approx. 0.7...1.0 V (related to the
reference value).
♦ The voltage signal „lean mixture (high level of residual
oxygen)" is at approx. 0.0...0.3 V (related to the
reference value).
♦ A voltage jump from 0.7...1.0 V to 0.0...0.3 V and vice
versa occurs at the transition from „rich" to „lean" and
vice versa ( = 1.0).
Edition 11.98
S00.5109.51.20
Self-Diagnosis
Possible cause of fault
♦ Open circuit in wiring caused by:
Lambda probe or
Signal wire or
Engine control unit
♦ Short circuit to earth caused by:
Lambda probe or
Signal wire or
Engine control unit
- Test lambda probe ⇒ page 24-12
- Test lambda probe ⇒ page 24-12
♦ In view of the steep voltage jump, the lambda control is
not able to hold constant the ideal mixture composition,
which corresponds to
fluctuates back and forward between the „slightly too
lean" and „slightly too rich" states.
♦ The readout must occasionally be below 0.3 V and
occasionally above 0.6 V. Readouts below 0.45 V
indicate a lean mixture, above 0.45 V a rich mixture.
K Lambda probe voltage U in mV
A: Lambda probe voltage high
♦ rich mixture (fuel excess or air deficiency)
♦ high CO concentration
B: Lambda probe voltage low
♦ lean mixture (fuel deficiency or air excess)
♦ low CO concentration
Rectifying fault
= 1.0. The control constantly
------------ ------------
01