S4 Quattro Sedan V6-2.7L Turbo (APB) (2000)
26, 2001.
If no leaks are found:
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Check fuel quality, drain fuel and replace with a quality Premium fuel as necessary (only with engine running rough).
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Check connection and condition of vacuum hose to fuel pressure regulator (located in fuel rail).
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Check fuel pressure regulator and replace if necessary (see Repair Manual, Repair group 24).
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Check coolant temperature sensor -G62- and replace if necessary (see Repair Manual Fuel Injection & Ignition Repair Group 01).
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Inspect air filter for proper installation and replace if damaged.
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Check flange connection between turbo charger and exhaust pipe for leaks.
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Check for sufficient fuel supply (consider DTC P1250).
If No leaks are found in the pressure side air duct and additional checks have been performed with No cause found and:
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In Display group 032:
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If channels 2/4 (arrows) are over +7%
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Symptom indicates the MAF sensor requires replacement:
If No leaks are found in the pressure side air duct and additional checks have been performed with No cause found and:
In Display group 204 (Biturbo only!):
If Channel 2 (black arrow) is more than 70mbar less than channel 4 (white arrow).