DTC P1507 (ISC_SHI): Idle Control System Malfunction (Fail-Safe)
- Connect scan tool. Retrieve DTC(s). If DTC P0505 also exists, diagnose DTC P0505. DO NOT diagnose DTC P1507. If only DTC P1507 is set, go to next step.
- Start and allow engine to idle. Check intake manifold, idle air control (IAC) valve and throttle body for loose installation or cracked gaskets. Check by-pass hoses for loose connection or cracking and vacuum hoses for disconnection or cracking. Repair as necessary. If no damage is noted, replace IAC valve.