Engine management system Chevrolet Aveo 1.5 (T250)

Description of the idle speed control circuit
The ECM controls engine idle speed using the Idle Air Control (IAC) valve. To increase idle speed, the ECM moves the IAC rod out of its socket, allowing more...

Diagnostic instructions
If the idle speed is too high, stop the engine. Pull the IAC idle air control valve handle out fully using the IAC actuator. Start the engine. If the idle...

Initial setting of idle system parameters
Each time the battery cable or connector is disconnected or replaced, the following information gathering procedure must be performed. Turn on the ignition for...

Removal the idle air control valve
Caution: Do not attempt to remove the protective cap to re-adjust the upper bolt. Incorrect adjustment may result in damage to the idling Air Flow Control...

Installing the Idle Air Control Valve
Caution: When installing a new IAC valve, ensure that it is replaced with an identical part. The IAC valve stem geometry and diameter are designed for a...

Manifold Absolute Pressure Sensor
The control system consists of sensors that provide detailed information about the state of the engine systems, electronic control unit and actuators. The...

Inlet air temperature sensor
The Inlet Air Temperature (IAT) sensor is a negative temperature coefficient thermistor. The sensor resistance is 4,500 ohms at 40°C and 70 ohms at 130°C. The...

Coolant Temperature Sensor (CT)
The coolant temperature sensor (ECT) is a thermistor (a resistor with a value that changes as the temperature changes) with a negative temperature coefficient...

Oxygen sensor (unleaded fuel only)
Three-way catalytic converters are used to control hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxides (NOx) in the exhaust. The catalytic agent in the...

CO regulator (leaded fuel only)
CO regulator (potentiometer), typically a variable resistor that regulates carbon monoxide (CO) emissions from vehicles running on leaded fuel. On such...

Throttle Position Sensor (TP)
The throttle position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body. The TP sensor circuit consists of a 5-volt supply...

Throttle body
Removal 1. Disconnect the "-" battery cable. 2. Remove the feed pipe from the throttle body. 3. Disconnect the throttle control cable. 4. Remove the vacuum...

Knock sensor
The knock sensor detects abnormal engine knocking. The sensor is mounted on the engine block near the cylinders. The sensor produces an AC output voltage that...

Crankshaft position sensor (CPS)
The direct ignition system operates with the help of a magnetic crankshaft position sensor. This sensor projects from its mounting socket by approximately 1.3...

Camshaft Position (CMP) Sensor
The camshaft position sensor sends a CMP signal to the engine control module. The ECM uses this signal as a timing pulse to fire the injectors in the proper...

Engine control unit
The Engine Control Module (ECM), located under the passenger dash, is the control center for the fuel injection system. It constantly monitors information from...

Comprehensive diagnostics of components
Comprehensive component diagnostics are required to check the powertrain components for intake and exhaust. Intake Components The intake components are...

Ignition system
This ignition system does not use a breaker-distributor and coil. Instead, it uses a crankshaft position sensor that sends a signal to the engine control...

Checking the ignition system
Check all spark plugs. Are there any wet, cracked, burnt, heavily fouled or improperly gapped spark plugs? Replace spark plugs if necessary. Check for spark...

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