Federal

Idle Speed Control (ISC) Servo Circuit:

To test the Idle Speed Control (ISC) Servo, located on the throttle body, proceed as follows.
1. Disconnect the ISC motor connector.

Idle Speed Control (ISC) Servo Test:

2. Check the continuity of the ISC motor coil between terminals 1 and 2.

Standard Value...5-35 ohm (@20°C/68°F)

Idle Speed Control (ISC) Servo Test:

3. Connect 6V DC (four dry cells) between terminal 1 and terminal 2 of the ISC motor connector, and check to be sure that the ISC servo operates.
4. Connect 6V DC (four dry cells) in reverse polarity than in step 3, between terminal 1 and terminal 2 of the ISC motor connector and check to be sure that the ISC servo operates.
CAUTION: Apply only a 6V DC or lower voltage. Application of higher voltage could cause locking of the servo gears.

4. If the servo does not operate, replace it as an assembly.

Harness Test

1. check ECU harness terminals 10 and 23 for an open circuit, or a short to ground.
2. If the harness fails this test, repair it.