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Idling speed controller (see photo 1) is a device that is needed in the system for the stabilisation of turns of idling of the engine. The IAC is a stepper motor with a spring-loaded tapered needle.

During operation of the engine at idle, due to the change in flow rate over an additional channel for supplying air to bypass the closed throttle valve, supplied to the engine required for stable operation, the amount of air. This air is taken into account by the sensor mass air flow (MAF) and, in accordance with its quantity, the controller operates the fuel supply to the engine via fuel injectors. The crankshaft position sensor (ДПSW) the controller monitors the number of revolutions of the engine and in accordance with the mode of operation of the engine controls the IAC, thus adding or reducing the flow of air to bypass the closed throttle valve (see photo 2 and photo 3).

On a warmed-up engine, the controller is in the idle. If the engine is not warmed up, the controller due to the IAC increases turnover and, thus, provides warming up the engine at high rpm of the crankshaft. This mode allows the engine to start the vehicle immediately and not warming up the engine. Idling speed controller installed on the throttle body (see Photo 4) and fixed thereto by two screws. Unfortunately, on some cars the heads of these screws mo - gut to be reamed or screws planted on the lacquer, which can considerably complicate the dismantling of the IAC to replace or clean the air channel. In such cases it is rarely possible to do without removing the whole throttle body. The IAC is the Executive device and its self-test not available in the system. Therefore, when malfunctions of the idling regulator lamp "CHECK ENGINE" light does not illuminate.

The symptoms of faults IAC is much the same malfunctions TPS sensor (position sensor Dros - selnau damper), but in the second case often all th a defective TPS clearly indicates the lamp "CHECK ENGINE". To the fault of the idling regulator may include the following symptoms: erratic engine speed at idle, spontaneous increase or decrease engine speed, stop the engine by turning off the transmission, no high revs when starting a cold engine, reducing idling speed of the engine when the load (lights, heater, etc). For disassembly of the regulator idling is necessary when the ignition is switched off to disconnect the four-pin connector and Unscrew the two fixing screws. Installation IAC produce in reverse order, but after checking the distance from the flange to the end point of the cone of the needle, which must be 23 mm. furthermore, the o-ring on the flange should be lubricated with engine oil.

Failure of the idle speed regulator

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