Porsche DME 7.8 — OBD II Diagnosis Manual / PAGE 528
DME 7.8 DME 7.80 · Work instruction Display OK
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DME 7.8 DME 7.80
Work instruction Display OK If not OK
2 Perform system test for See below
small lift
3 Replace TWC
Perform system test for small lift
Warning!
During the system test for small lift, the valves remain at small lift,
regardless of the type of driving. Faulty switching conditions can be
detected by rough running, just like with misfire detection. If a valve
is not switched to small lift, the fault type "below limit" is recorded.
Several cylinders may be stored as faulty, although only one valve
on one cylinder is faulty.
In order to ensure that the fault is repaired, the flat-base tappets of
the inlet valves of the entire cylinder bank should be replaced if a
fault occurs.
A faulty flat-base tappet can be detected because the oxygen sen-
sor FR for this cylinder bank enriches the mixture (FR > 1) during
acceleration with wide-open throttle ⇒ see drawing below. Differ-
ence from the other oxygen sensor > approx. 15 %. In the case of a
fault, the flat-base tappets of the inlet valves for the entire cylinder
bank must be replaced.
0-63 page 2 2673 P0430
p0430 Printed in Germany – 1, 2000
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