Extended Idle Air By-Pass System
- With engine at normal operating temperature and transmission in "N", begin timing. If after 2 1/2 minutes thermactor by-pass valve dumps secondary air through vents, system is okay. If not, check routing and condition of hoses. If hoses are okay, check by-pass valve function.
- If valve is okay, check battery voltage to ITS and continuity through normally closed ITS while manually cycling switch. If okay, check that solenoid is functional and actually opens to close off vacuum. If solenoid is okay, turn engine "OFF" and ignition "ON". After 2 1/2 minutes, check vacuum signal to solenoid.