Troubleshooting Hints

Hint 1: If the stepper motor step increases to 100 to 120 steps or decreases to 0 step, faulty stepper motor or open circuit in the harness is suspected.

Hint 2: If the idle air control motor harness and individual part checked good but the stepper motor steps are out of specification, the following faults are suspected.

1. Poorly adjusted reference idle speed
2. Deposit on the throttle valve
3. Air leaking into the intake manifold through gasket gap
4. Loose EGR valve seat
5. Poor combustion in the cylinder (faulty ignition plug, ignition coil, injector, low compression pressure, etc.)