Mirage L4-1597cc 1.6L DOHC (1990)
2. Using an ohm meter, check the resistance between terminals 5 and either 6 or 4.
Resistance
28 - 33 ohms @68°F
Idle Speed Control (ISC) Servo Operation Test
3. Using a 6 VDC power supply, apply voltage to terminals 2 and 5.
4. While holding the servo as indicated in the image, connect the negative terminal of the supply to each pair of terminals in the order given below.
The servo should vibrate when the ground circuit is supplied.
a. Connect the negative power supply to terminals 3 and 6.
b. Connect the negative power supply to terminals 1 and 6.
c. Connect the negative power supply to terminals 1 and 4.
d. Connect the negative power supply to terminals 3 and 4.
e. Connect the negative power supply to terminals 3 and 6.
f.
Perform the tests in reverse order from step e to a.
5. Replace the servo if does not vibrate during each test.
CAUTION: Do not apply a voltage higher than 6 Volts. If a higher voltage is used, damage to the ISC servo can result.
OSCILLOSCOPE TEST
1. Connect the probe of the scope to the four points shown in the image.
Oscilloscope Test
2. Idle the engine and observe the pattern when the A/C (or any electrical load) is placed on the engine.
NOTE: Since the ISC motor only operates to change the idle speed, the pattern will only be visible when it operates.
HARNESS TEST
1. Turn the key to the ON position.
2. Disconnect the ISC connector.
3. Using a volt meter, check the voltage between ISC connector harness terminal 2 and ground.
