A8L V8-4.2L (BFM) (2004)
Camshaft Position Sensor: Testing and Inspection
Camshaft Position (CMP) Sensor -G40- And Camshaft Position (CMP) Sensor 2 -G163-, Checking
The Camshaft Position (CMP) sensor provides the ignition position for cylinder 1.
For failure, knock control is switched off and the ignition angle is retarded slightly since a cylinder allocation is no longer possible.
Engine will continue to run without Camshaft Position (CMP) sensor signal and can also be restarted:
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When a malfunction is recognized, the Engine Control Module (ECM) initiates one ignition spark per cylinder for each crankshaft rotation.
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The offset of one engine rotation will have no noticeable effect on the injection. Instead of occurring with intake valves open, injection will be
"pre-loaded" (in front of closed intake valve). This has only a minor effect on the quality of the mixture preparation.
NOTE:
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Camshaft Position (CMP) Sensor 2 -G163- is located at rear of left cylinder block (bank 2).
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Camshaft Position (CMP) Sensor -G40- is located at front of right cylinder block (bank 1).
Checking activation of Camshaft Position (CMP) sensor
Cables from V.A.G 1594 connector test kit must be used for the following tests.
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Slide back rubber grommet on connector of respective Hall sensor.
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Connect V.A.G 1527 voltage tester between terminal 1 (B+) and 2 (Hall sensor signal) from rear to Hall sensor connector (connector remains
connected to Hall sensor).
NOTE: Connector sockets are numbered respectively on the rear side of the connector.
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Operate starter for a few seconds.
Diode test lamp must blink briefly at every second engine rotation.
NOTE: Diode test lamps do not go out completely during low current pick-up between activations by the ECM, but rather continue to glow a
little and then get significantly brighter during activation.
If voltage test lamp does not blink, check voltage supply.
Checking voltage supply of Camshaft Position (CMP) Sensor
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Disconnect connector at respective Camshaft Position (CMP) sensor.
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Switch ignition on.