Volkswagen Golf 1999 Service Manual page 676

Measured value (data) blocks
Evaluating display group 32, display zones 1 and 2 - Oxygen Sensor (O2S) learned
values before Three Way Catalytic Converter (TWC)
Appears on
display
Low Oxygen
Sensor (O2S)
learned
values
http://ebahn.bentleypublishers.com/vw/servlet/Display?action=Next&type=repair&id=...
Possible cause
Low learned values at idling
but with normal learned
values at part throttle/load:
possible oil dilution (high
level of fuel in oil)
Fuel injector leaking
Fuel pressure too high
Evaporative Emission
(EVAP) Canister Purge
Regulator Valve -N80-
permanently open
Mass Air Flow (MAF) Sensor
-G70- faulty
Oxygen Sensor (O2S)
heating faulty or Oxygen
Sensor (O2S) contaminated
Continuation
Corrective action
- Disappears after
freeway/expressway driving or oil
change
- Check fuel injectors
- Check fuel pressure control and
holding pressure
- Check Evaporative Emission
(EVAP) Canister Purge Regulator
Valve -N80- Page 01-100
Output Diagnosis Test Mode (DTM)
- Check Evaporative Emissions
(EVAP) Canister system:
Repair Manual, 2.8 Liter VR6 4V
Engine Mechanical, Engine Code(s):
BDF; Repair Group 20
- Check Mass Air Flow (MAF)
Sensor -G70-
- Check Oxygen Sensor (O2S)
heating before Three Way Catalytic
Converter (TWC)
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12/2/2005