Camshaft position (CMP) sensor -G40-, checking: Notes

Special tools and workshop equipment required

V.A.G 1526 A
V.A.G 1527 B
V.A.G 1594 A
V.A.G 1598/31

Fig 1: Identifying Special Tools

Courtesy of AUDI OF AMERICA, INC.

Component location. See item 18 in COMPONENT LOCATIONS, OVERVIEW .

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.

When a malfunction is detected, the ECM produces one spark for each cylinder on every crankshaft revolution.
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 inlet valve) instead of while the inlet valve is open. This has only a minor influence on the quality of the air/fuel mixture.