Audi AMB Service Manual page 225

ENGINE 1.8 Liter 4-Cyl. 5V Turbo Engine Mechanical, Engine Code(s): AMB
misfiring at high engine speeds.
Effects of leakage at intake and exhaust end
Leakage downstream of Mass Air Flow sensor
Effect: Loss of power

Possible fault sources:
1. Hose connection between mass air flow sensor and turbocharger
2. Connection hose to crankcase breather
3. Connection hose to mechanical air recirculation valve
Leakage downstream of turbocharger
Effect: Charge air pressure too low

Possible fault sources:
1. Connection hoses and line between turbocharger and charge air cooler
2. Hose between charge air cooler and intake manifold
3. Charge air cooler
4. Gasket of Charge air pressure sensor G31 (in charge air cooler)
5. Gasket between throttle valve control module and intake manifold
6. Gasket between intake manifold and cylinder head
CHARGE PRESSURE LEAK TEST WITH VAG1687
Intake system, checking for leaks using Diagnostic Tool VAG1687
Diagnostic trouble codes (DTCs) related to fuel trim, charge pressure or mass air flow (MAF) may be caused
by:
Leaking (worn/torn) intake hoses during charge conditions

Incorrectly torqued or improperly placed clamps on intake hoses etc. causing leaks during charge

conditions
2005 Audi A4 Quattro
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