Diagnostic Aids

The throttle valve is spring loaded to a slightly open position. The throttle valve should be open approximately 20-25 percent. This is referred to as the rest position. The throttle valve should not be completely closed nor should they be open any more than the specified amount. The throttle valve 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. Replace the throttle body if any of these conditions are found.

IMPORTANT: 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 valve using the throttle blade control 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.

Inspect for the following conditions:

Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
Poor connections at the ECM or at the component-Inspect the harness connectors for a poor terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections for the proper procedure.
For intermittents, refer to Testing for Intermittent Conditions and Poor Connections .