Camshaft Hall sensor function - GF07.04-P-4117-02F
The signal cable of the camshaft Hall sensor has a voltage signal of approx. 12 V ("high"). If, however, the segment (a) at the camshaft sprocket (1) is just moving past the camshaft Hall sensor at that moment, the signal jumps to 0 V ("low").
This "0 V signal" is used for detecting ignition TDC of cylinder 1 (engine 120: second camshaft Hall sensor for additionally detecting ignition TDC of cylinder 7, left cylinder bank)
Shown on engine 120
The distance between the Hall sensor on the camshaft and the segment of the camshaft sprocket of the exhaust camshaft or the segment at the camshaft adjuster is not adjustable.
If no signal is received from the camshaft Hall sensor, the engine control unit determines the ignition TDC of cylinder 1 at random. The engines start about 1 second later and the emission levels at start are not optimal.
Engine 119 starts only if the ignition TDC of cylinder 1 has been correctly determined by chance. Engine may possibly start only at further attempt.