Codes 12 & 13 - Idle Speed Control Test
- Check and adjust curb idle if needed. Disconnect the ECA from the vehicle wiring harness. Connect an ohmmeter across terminals 9 and 10 of ECA plug J2. Resistance should be 6-14 ohms.
- If resistance is incorrect, check resistance at solenoid terminals. If resistance is correct (6-14 ohms), locate and repair short in wiring harness leading to solenoid. If resistance between terminals 9 and 10 is still incorrect, replace ISC solenoid. Reconnect ECA and ISC solenoid.
- Turn ignition switch on and check voltage at Red wire in ISC solenoid connector. If voltage is not 10.5-volts or greater, find and repair open circuit in Red wire leading to solenoid. Check for 10.5 or more volts at Purple wires in ISC connector. If not present, check for short circuits in Purple wires leading to ISC.
- Connect voltmeter (0-20V) to rear of ISC harness connector with ISC connected. Repeat Quick Test while observing voltmeter. If meter reading varies during Quick Test, replace ISC solenoid.
- Connect voltmeter to rear of ECA connector J2 pins 11 and 9. Repeat Quick Test. If meter reading varies during Quick Test, isolate and repair open circuits in Purple wires leading to ISC. If meter reading does not vary during Quick Test, check ECA connectors for bent or damaged pins. If connectors are good, replace ECA.