GENERAL INFORMATION
Description
The Engine Control Module (ECM) controls the engine management system. The ECM can adjust for varying driving
conditions and modify fuel and ignition requirements as needed to maintain optimum performance and economy.
The following are the input and output components monitored by the ECM.
ECM Inputs
• Brake Switch Sensor
• A/C Pressure Sensor
• Refrigerant Pressure Sensor
• Camshaft Position (CMP) Sensor
• Crankshaft Position (CKP) Sensor
• Engine Coolant Temperature (ECT) Sensor
• Manifold Absolute Pressure (MAP) Sensor
• Throttle Position Sensor (integral with Electronic Throttle Control Actuator)
• Power Steering Switch
• Accelerator Pedal Position (APP) Sensor
• Knock Sensor
• Upstream Oxygen Sensor
• Downstream Oxygen Sensor
• Vehicle Speed Sensor
• Clutch Pedal Switch
ECM Outputs
• Canister Control Valve
• Fuel Injectors
• Fuel Pump Relay
• Electronic Throttle Control Actuator
• Ignition Coil
• A/C Compressor
• Cooling Fan
• Oxygen Sensor Heater (Upstream & Downstream)
Operation
The ECM monitors components and circuits and tests them in various ways depending on the hardware, function,
and type of signal. For example, analog inputs such as throttle position or engine coolant temperature are typically
checked for opens, shorts and out-of-range values. This type of monitoring is carried out continuously. Some digital
inputs like vehicle speed or crankshaft position rely on rationality checks - checking to see if the input value makes
sense at the current engine operating conditions. These types of tests may require monitoring several components
and can only be carried out under appropriate test conditions.
The ECM is a pre-programmed, microprocessor-based digital computer. It regulates ignition timing, air-fuel ratio,
emission control devices, charging system, certain transmission features, speed control, air conditioning compressor
clutch engagement and idle speed. The ECM can adapt its programming to meet changing operating conditions.
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Chery Automobile Co., Ltd.
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