P0171,P0172
Symptom: CHECK ENGINE lamp (MIL) on
Adaptation too lean or too rich, rear cylinder row (cyl. 1-3-5)
Fault symptom
CHECK ENGINE lamp (MIL) on
Condition
More than 25%%richer or leaner for at least 20
seconds.
If other diagnostic trouble codes are present, deal with them first.
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1.
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Activate the ISAT command
"ADAPT. SHORT 1-3-5" or "ADAPT. LONG
1-3-5" in the "READ FUNCTIONS" menu to see whether the engine is
running on a lean or rich mixture. Lambda 1 corresponds to 0%%on the
ISAT.
"ADAPT. SHORT" displays the current fuel-air mixture and "ADAPT.
LONG" shows the mean value of the mixture over the past 15-20 minutes.
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2.
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Clear all trouble codes and drive the car to check whether any
trouble codes are generated afresh. It they are, continue as described
below.
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3.
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Check the following points:
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that the oxygen sensor's signal lead is not in
contact with any HT
lead
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that components of the correct type are fitted in the fuel system
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that no air leakage occurs in the induction system
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that fuel pressure is correct
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that battery voltage is correct
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that no leakage occurs in the exhaust system ahead of or behind the
oxygen sensor
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that all grounding points in the system are OK
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4.
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If no fault can be detected after carrying out the above checking
procedure, clear the trouble code and drive the car on the road to
check whether the trouble code is generated afresh. If it is, turn to
for further diagnostic instructions.
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