Porsche DME 7.8 — OBD II Diagnosis Manual / PAGE 932
DME 7.8 DME 7.8 0 · ♦If a fault is detected, it is only recorded in the
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DME 7.8 DME 7.8 0
Note!
♦If a fault is detected, it is only recorded in the fault memory after
6,000 ignitions (at idling speed approx. 3 minutes waiting time).
♦It is important to observe the oxygen sensor during acceleration
with wide-open throttle or to record its behaviour with the data
logger.
♦If misfires are stored, see Troubleshooting misfires.
629 Valve lift control, cylinder 2 - below limit
Diagnosis conditions
• Speed between 2,000 and 3,320 rpm
• Load between 45 and 70 %
• Acceleration with wide-open throttle
Possible fault cause
♦A valve does not switch to small lift
♦Several valves (various cylinders) do not switch to small lift
Affected terminals
-
Diagnosis/troubleshooting
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 ’under limit’ is recorded.
Several cylinders may be stored as faulty, although only 1 valve on
one cylinder is faulty.
In order to guarantee safety during repairs, the flat-base tappets of
the inlet valves of the entire cylinder bank should be replaced if a
fault occurs.
1555 P1353 0-159 page 3
Printed in Germany, 2000 p1353
This is a source reference. Confirm exact model applicability in the original material.
