Gauges and Indicators

Gauges and Indicators

How the Circuit Works

The indicators are controlled by relative conditions in their associated systems

Refer to each associated system to see its entire schematic.

Coolant Temperature Gauge

The coolant temperature gauge is controlled by the CPU circuit built-into the gauge assembly. The CPU circuit receives coolant temperature information from the PCM. The PCM receives coolant temperature information from the ECT sensor.

Fuel Gauge and Low Fuel Indicator

WARNING: Do not smoke while working on the fuel system.Keep open flame away from the work area.Drain fuel only into an approved container.

The fuel gauge and low fuel indicator are controlled by the CPU circuit built-into the gauge assembly. The CPU circuit receives fuel level information from the fuel gauge sending unit.

The fuel gauge sending unit's resistance varies from about 11-13 ohms at full to about 130-132 ohms at empty. The fuel level current changes with the varying resistance, which enables the CPU circuit to determine the level of the fuel. When the CPU circuit determines that the fuel level is low, it turns the low fuel indicator on. When the ignition switch is turned to LOCK (0), the gauge returns to the bottom of the gauge dial regardless of the fuel level.

Speedometer and Odometer

The odometer and the speedometer are controlled by the CPU circuit built-into the gauge assembly. The CPU circuit receives pulses from the PCM. The pulse rate increases as the car accelerates. The CPU circuit measures the frequency and duration of these input pulses and converts the pulses into mph and mileage readings.

Tachometer

The tachometer is controlled by the CPU circuit built-into the gauge assembly. The CPU circuit receives pulses from the PCM. The pulse rate increases as the engine speed increases. The main circuit measures the frequency and duration of these input pulses and converts the pulses into engine rpm readings.