Bosch Motronic - Component Datasheet
Crankshaft Position Sensor (G4)
The crankshaft position sensor (aka CPS), referred to as G4 in the schematic is used by the ECU to determine a specific position in the rotational position of the crankshaft. A steel pin is pressed into the flywheel at 62 degrees BTDC for cylinder #1. This pin triggers a reference signal once per engine revolution that the ECU uses to establish a reference point against other signals.
is located on the left side of the engine near the flywheel. It is mounted
alongside the crankshaft speed sensor (G28) and care must be taken not to
confuse the wiring of these two sensors as they are identical in design.
G4 fails, the engine cannot be restarted but if G4 fails whilst the engine is
running then it will continue to run by making the fair assumption that the
flywheel reference pin has not moved since the engine started !
Last Updated 9th November 2007