Envoy 2WD V8-5.3L VIN M (2005)
Engine Control Module: Description and Operation
Electronic Ignition (EI) System
ENGINE CONTROL MODULE (ECM)
The engine control module (ECM) controls all ignition system functions, and constantly corrects the basic spark timing. The ECM monitors information
from various sensor inputs that include the following:
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The throttle position (TP) sensor
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The engine coolant temperature (ECT) sensor
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The mass air flow (MAF) sensor
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The intake air temperature (IAT) sensor
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The vehicle speed sensor (VSS)
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The transmission gear position or range information sensors
