Diognosing the Idle Air Control

HERE ARE TIPS ON THE IDLE AIR CONTROL

The first step to diognose the idle air valve is to verify that it is or isn't working. To do this, have engine warmed up and idling. Unplup the 2 wire plug from the control, and the engine should either die, or idle very slowly. If it doesn't slow down or stall, the base idle setting may be too high, or the idle valve is bad or clogged with crud. Next take a digital volt meter hook the neg lead to the battery neg, and probe the pos lead to both of the terminals of the harness, and one should have 10.5 volts or more. Next measure the resistance across both terminals of the idle control valve, and it should show 7 to 13 ohms. If the resistance is off, the valve is bad. If the voltage is not 10.5 volts or more, there is a wiring problem. If all checks out good so far, remove the control valve and clean it thouroughly. Reinstall it, and leave it unplugged. Start engine, and verify that engine idles slow, or stalls. Shut engine off, pull battery cable off for at least 15 minutes, then reconnect. Start and drive car for a half hour or so for it to relearn its idle strategy. Note that a dirty throttle body will also affect the idle and stalling when the control is unplugged, so this would also be a good time to clean it.I reccomend removal to clean, as one factor that sets lots of codes is the sludge build up that plugs the vachum passages of the throttle body, and removal is necessary to insure a clean body.