Idle Speed/Throttle Actuator - Electronic: Testing and Inspection

Idle Speed Control Solenoid Schematic:

A faulty idle speed control (ISC) solenoid will set code 24 in the on-board diagnostic system. Refer to the schematic diagram and test the solenoid with the diagnostic chart.

Wire color code identification:

L: Blue
B: Black
Y: Yellow
G: Green
R: Red
W: White
Br: Brown
Lg: Light green
Gr: Gray

Idle Speed Control Solenoid Diagnostic Chart:

ISC SOLENOID DIAGNOSTIC CHART

Idle Speed Control Solenoid Testing:

CHECK ISC OPERATION, VOLTAGE AND RESISTANCE

1. Connect "Test Mode" connector of on-board diagnostic system.
2. Turn ignition "ON."
3. Check ISC solenoid valve for operating vibration at 0.5 second intervals. Do not confuse ISC solenoid sound with CPC solenoid sound.
4. Turn ignition "OFF" and disconnect ISC harness connector (F114).
5. Turn ignition "ON" and measure voltage across harness connector terminal (F114)2 and ground. It should be above 9V.
6. Turn ignition "OFF" and measure resistance across harness connector terminals (F114)1 and (F114)2. It should be 20-30 Ohms at 20° C (68° F).
7. Measure resistance between ISC solenoid valve connector terminals #1 and #2. It should be 20-30 Ohms at 20° C (68° F).

ECU/Crank Angle Sensor Harness Testing:

CHECK ECU HARNESS

1. Disconnect ECU connector.
2. Measure resistance between ECU and ISC solenoid connectors as follows:

Connector & terminal: Resistance:
(F119)24-(F114)1 Below 1 Ohm
(F119)24-Ground Infinite

3. Measure resistance between ECU and ground as follows:

Connector & terminal: Resistance:
(F119)13-Ground Below 10 Ohms
(F119)26-Ground Below 10 Ohms

CHECK ECU VOLTAGE

1. Connect ECU and ISC solenoid connectors.
2. Disconnect "Test Mode" connector.
3. Turn ignition "ON" and measure voltage between ECU connector terminal (F119)24 and ground. It should read above 8V.