How to test idle air control valve？
First, we need to know what does the idle air control valve do.
The idle air control valve is powered by the ignition switch, as long as the ignition switch is turned to the ON position, the idle air control valve is energized and the engine computer controls its circuit override. When the engine operating parameters deviate from the normal value, the valve is used to adjust the idling speed. It is used for the opening of the bypass air passage of the EFI system to adjust the bypass air volume so that the engine speed reaches the required target value.
idle air control system and idle air control valve detection
First, idle air control system on the car test
(1) engine idling condition detection
After starting the engine in the cold state, when the warm-up process begins, the idling speed of the engine should reach the specified fast idling speed (usually 1500r/min); after the engine reaches the normal working temperature, the idling speed should return to normal (usually 750r/min). If the idle speed cannot change according to the above rule after cold start, the idle air control system is faulty.
After the engine reaches the normal working temperature, the engine idle speed should rise to about 900r/min when the air conditioning switch is turned on. If the engine speed drops after opening the air conditioning switch, the idle air control system is faulty.
In the engine idling, if the idle speed adjusting screw for micro rotation, the engine idle speed should not change (after rotation should make the idle speed adjusting screw back to the original position). If the idle speed changes in the rotation, the idle air control system does not work.
(2) idle air control valve working condition check
(3) ECU control voltage detection
Second, the idle air control valve detection
(1) Idle air control valve coil resistance detection
Remove the idle air control valve and measure the resistance value of the idle air control valve coil with a multimeter Ω file (Figure 2). Pulse linear solenoid valve idle air control valve has only one set of coil, its resistance value is 10-15Ω stepper motor idle air control valve usually has 2-4 sets of coil, the resistance value of each set of coil is 10-30Ω. if the coil resistance value is not in the above range, the idle air control valve should be replaced.
(2) The action of stepping motor check
The battery power is fed to each coil of the stepper motor in a certain order to make the stepper motor rotate. The coil form and terminal arrangement of various stepper motors are different. Here, take the Crown 3.0 sedan 2JZ-GE engine idle control valve stepper motor as an example to explain its inspection method. First of all, the stepper motor connector terminal B; and B and the positive battery connected, and then the terminal S, S, SS in turn (SSS, S;) and the negative battery connected, at this time the stepper motor should rotate, the spool to the outside, if the terminal S1, S2, S, S. In the opposite order (SS-SS) and the negative battery connected, the stepper motor should rotate in the opposite direction, the spool to the inside retracted into
