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Home >> Audi >> 1998 >> A8 Base >> Repair and Diagnosis >> Engine Performance >> System >> Ignition/Glow Plug System - 3.7L & 4.2L V8 (AEW, ABZ) >> Ignition System >> Camshaft Position (CMP) sensor, checking >> Notes

Camshaft Position (CMP) sensor, checking: Notes

The Camshaft Position (CMP) sensor -G40- is located on the rear of the left cylinder head. See COMPONENT LOCATIONS, OVERVIEW .

NOTE:
  • During normal engine operation the ECM, using the CMP sensor signal, recognizes the ignition point for cylinder 1 and initiates ignition for each cylinder at every second crankshaft revolution.
  • The engine will start or run with a faulty or disconnected CMP sensor, since the ECM initiates ignition for each cylinder with ever crankshaft revolution after recognizing the malfunction.
  • For the fuel injection, being off by one crankshaft revolution has no noticeable effect. Fuel is injected against the closed intake instead of taking place while the valve is open. The quality of the fuel/air mixture is not significantly affected.
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