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Home >> Land Rover >> 1999 >> Range Rover (LP) V8-4.6L >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Relays and Modules - Computers and Control Systems >> Main Relay (Computer/Fuel System) >> Description and Operation
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Main Relay (Computer/Fuel System): Description and Operation



With GEMS (Generic Engine Management System)

Main Relay
This relay supplies the power feed to the ECM (Z132) with a tap off to feed the fuel injectors and air flow meter. This relay is controlled by the ECM (Z132) itself, so that the ECM (Z132) remains powered up after the ignition is removed and the ECM (Z132) can record all temperature readings and motorize the Idle Air Control Valve (M112) to the fully open position. This is known as the "ECM (Z132) power down routine". Failure of this relay will cause the ECM (Z132) to not be switched on, resulting in absence of fuel and spark and therefore a failed start.
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