Tachometer: Description and Operation

How the Circuit Works

The indicators are controlled by relative conditions in their associated systems. For the following indicators the information supplied to the gauge assembly is received via the multiplex control unit:
- Charging System
- Door/Hatch Indicator Light
- Maintenance Required Indicator
- Seat Belt Reminder

Tachometer
The tachometer is controlled by the CPU built-in the gauge assembly. The CPU receives pulses from ECM/PCM. The pulse rate increases as the engine speed increases. The frequency and duration of these input pulses are measured by the CPU.