A4 Cabriolet L4-1.8L Turbo (AMB) (2005)
Camshaft Position Sensor: Testing and Inspection
With Manufacturer's Scan Tool
Camshaft Position (CMP) Sensor -G40-, Checking
Special tools and workshop equipment required
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V.A.G 1526 A Multimeter
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V.A.G 1527 B Voltage tester
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V.A.G 1594 A Connector test kit
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V.A.G 1598/31 Test box
Component location Figure 18.
The Camshaft Position (CMP) sensor -G40- indicates the ignition position for cylinder 1.
If the Camshaft Position (CMP) sensor -G40- fails to function, the knock recognition control is switched off and the ignition timing is retarded slightly
because the signals can no longer be assigned to the cylinders. Furthermore, the charge pressure of the turbocharger is lowered.
Even without a signal from the Camshaft Position (CMP) sensor -G40-, the engine will continue to run and can also be restarted.
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When a malfunction is detected, the ECM produces one spark for each cylinder on every crankshaft revolution.
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The fact that the ECM is out of phase by one engine revolution does not have any noticeable effect on the injection system. If this happens, the fuel
is injected "upstream" (before the closed intake valve) instead of while the intake valve is open. This has only a minor influence on the quality of
the air/fuel mixture.
Checking activation
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Push back rubber grommet of connector for Camshaft Position (CMP) sensor -G40- back but leave connector attached.