Idle Air Control (IAC) Valve
- Turn ignition off. Unplug IAC valve connector. IAC is located near throttle body. Turn ignition on. Measure voltage between Yellow/Black wire on harness connector and ground. If battery voltage exists, go to next step. If battery voltage does not exist, repair Yellow/Black wire between IAC valve and PGM-FI main relay.
- Turn ignition off. Connect test harness to vehicle wiring harness, not to ECM. See Figure . Turn ignition on. Momentarily connect terminal A9 (A5 on Odyssey) to terminal A23 (A12 on Odyssey, or A26 on Prelude). If IAC valve clicks, substitute known-good ECM and retest system. If IAC valve does not click, repair Black/Blue wire between IAC and ECM terminal A9 (A5 on Odyssey).