Warning. Before performing repair work on checking and replacing the idle speed regulator (IAC) read the precautions for repairing the engine management system (see "Precautions when repairing the engine management system").
To perform repair work on replacing the IAC, you will need:
- multimeter (in voltmeter and ohmmeter mode);
- wire segments.
Examination
1. We prepare the car for work (see points 1 and 2 "Preparing the car for maintenance and repair").
2. We release the latch connectors of the IAC wiring harness.
Disconnect the connector from the idle speed controller.
3. Connect «negative» voltmeter probe to «mass» engine.
4. Turning on the ignition, use a voltmeter to measure the voltage at terminals A and D of the wiring harness connectors (pin designations are printed on the connector).
Note. The voltage must be at least 12 V. If the voltage is not supplied to the connector or it is less than 12 V, then the battery is discharged, the power circuit is faulty or the computer is faulty.
Warning. Turn off the ignition after the voltage measurement is completed.
Removing
1. Using a Phillips screwdriver, unscrew the two screws securing the idle speed controller to the throttle body.
2. Remove the idle speed regulator.
3. Using an ohmmeter, we measure the resistance between the terminals of the IAC windings.
Note. The electrical resistance between terminals A-B and CD should be about 53 ohms. The resistance between terminals A-C and BD must be large (strive for infinity). A defective idle speed control must be replaced.
Installation
Warning. Before installing a new idle speed controller on a car, make sure that the valve needle protrudes no more than 23 mm.
1. Using a caliper with a depth gauge, we measure the protrusion of the needle of the new valve.
2. If the protrusion of the valve is more than 23 mm, then we sink the valve into the body as follows:
A) wire connect the positive terminal of the battery to the terminal D of the idle speed controller (IAC) (the connection of the wire to the output must be insulated);
b) with the bare end of the wire connected to the negative terminal of the battery, briefly touch terminal C of the harness connector. Since the valve moves very slowly, we perform touches repeatedly, reproducing the operation of a switching power supply.
3. External inspection check the condition of the sealing ring. Replace damaged ring.
4. We install on the car all the removed parts in the reverse order of removal.