Diagnostic Aids

Inspect for a condition in which the throttle valves may be held open.
Inspect for conditions in which ice may have formed in the throttle bore.

The throttle valves are spring loaded to a slightly open position. This is referred to as the rest position. The throttle valves should not be completely closed, nor should they be open any more than the specified amount. The throttle valves should move open and to the closed position without binding under the normal spring pressure. The throttle should NOT be free to move open or closed WITHOUT spring pressure.

NOTE: Operating the throttle blade with the Throttle Blade Control function of the scan tool may cause additional DTCs to set. DO NOT attempt to diagnose DTCs set during this function.

The scan tool has the ability to operate the throttle control system using Special Functions. Actuate the throttle valves using the Throttle Position function located in the TAC system menu. This function will operate the throttle valve through the entire range in order to determine if the throttle body and system operate correctly.

For intermittent conditions, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.