Discovery II (LT) V8-4.0L (2002)
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Tachometer: Description and Operation
Tachometer
The tachometer is an integral pan of the instrument pack. Located next to the speedometer. It displays engine speed in revolutions per minute. It is an
analogue gauge with a maximum reading of 6000 rev/min.
V8 and diesel variants use the same gauge.
The input for the tachometer is from the ECM. It is a digital signal at 2 pulses per engine revolution. When the ignition is switched on with the engine
not running, the ECM will generates pulses equivalent to 228 rev/min for diagnostic purposes. The tachometer will not register a reading, as it only
indicate engine speeds above 228 rev/min.
