Component description for camshaft Hall sensor - GF07.04-P-6020AMG

ENGINE 156.980 in MODEL 164, 251 up to Model Year 8

ENGINE 156.982 in MODEL 209

ENGINE 156.983 in MODEL 211, 219

ENGINE 156.984 in MODEL 216, 221 up to Model Year 8

Location

Fig 1: Identifying Left/Right Intake Camshaft Hall Sensor And Left/Right Exhaust Camshaft Hall Sensor

Courtesy of MERCEDES-BENZ USA

Task

The camshaft Hall sensors detect in a non-contact manner the positions of camshafts via pulse wheels for the following functions:

Camshaft adjustment (actuation and diagnosis)
Synchronization of the ignition and injection sequence (detection of Ignition-TDC).
Emergency start of the engine for a defective crankshaft Hall sensor (B70)

Design

The camshaft Hall sensor consists of a Hall sensor and integrated electronics which are cast into a plastic housing. It has a 3-pin plug connector and a proximity of 0.2 to 1.8 mm to the pulse wheel in its installation position.

Function

Detection of the positions of the camshafts takes place via recognition of positions of pulse wheels which are located at the front on the camshafts.

Four signals are generated for each camshaft revolution. Here the signals switch between about 5 volts (high) and 0 volts (low). If a "cutout in the pulse wheel" is opposite a Hall sensor, the signal is approx. 5 volts.

The positions of the camshafts is already detected for an engine OFF situation by the integrated electronics. This means that the exhaust emission values at an engine start are improved and the engine starts quicker, since the every cylinder during an engine start can be immediately assigned the optimal injection quantity (rapid start function).

Location of the cutouts on pulse wheels

Fig 2: Identifying Pulse Wheels Camshaft Angles

Courtesy of MERCEDES-BENZ USA

The specified angles on the pulse wheel are camshaft angles (Cam A) and must be doubled in order to obtain the corresponding crankshaft angle (CA).