A6 Quattro Wagon V6-2.8L (AFC) (1995)
Air/Fuel Mixture: Adjustments
Test conditions
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No leaks in exhaust system.
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Engine Coolant Temperature (ECT) minimum 85°C (185°F).
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Throttle valve in closed throttle position. Adjust accelerator pedal cable if necessary.
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All electrical consumers switched OFF.
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A/C switched OFF.
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Pressure measuring devices NOT connected.
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Automatic transmission vehicles: selector lever in P or N.
Checking CO Content
NOTE:
CO content cannot be adjusted manually.
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Remove cap screw from exhaust manifold, install adapter VAG 1318/12 and VAG 1732 hose stem.
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Connect CO tester VAG 1363 (or equivalent) with hose adapter VAG 1363/3, according to operating instructions.
NOTE:
CO tester hose adapter must fit tightly over hose stem so that there are no exhaust leaks.
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Check CO content.
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Specified value: 0.2-1.2% by volume
NOTE:
The following points are to be considered and checked:
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If the CO content is below 0.2% by volume, there may be leaks around the CO tap tube or the connection to the CO tester.
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If the CO content is above 1.2% by volume, the cause maybe leaks in the exhaust system between the engine and the heated oxygen sensor.
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Failure of a spark plug and/or a fouled spark plug causes an increase in the CO content of about 1.7%.
If specified value is not obtained:
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Check DTC memory.
If no malfunctions are stored in DTC memory:
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Activate "Read Measuring Value Block" function 08 with VAG 1551 and read display groups 005 and/or 006, display field 1 (oxygen sensor
control).