Main instrument unit, detailed description: Tachometer

Fig 1: Identifying Tachometer

Courtesy of SAAB-SCANIA OF AMERICA, INC.

The electronic tachometer shows the current engine speed. Information on the current engine speed is generated by the crankshaft position sensor, which measures the current engine speed. The sensor is wired to the engine control module, which converts the frequency to an engine speed bus message and transmits it on the P-bus. CIM forwards the message to the I-bus. The main instrument unit displays the bus message as current engine speed, RPM, on the tachometer.

There are two different types of graduation:

• Petrol 0-7000 RPM
• Diesel 0-6000 RPM