P0568

Circuit Description

The Throttle Actuator Control (TAC) Module is a communication link between the cruise switches and the PCM. The cruise Set/Coast switch is an input to the TAC Module. This input is then communicated from the TAC Module to the PCM across serial data, allowing the PCM to control and hold a requested speed. The Cruise Set/coast switch sends an ignition voltage to the TAC Module when the switch is closed (ON). If the PCM receives an input when the module does not expect it, this DTC sets.

Conditions for Running the DTC

The Cruise switch is ON.

Conditions for Setting the DTC

The Set/Coast switch is ON for longer than 90 seconds.

Action Taken When the DTC Sets

^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM will store conditions which were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

^ A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ DTC can be cleared by using the scan tool Clear Info function.

Diagnostic Aids

Important: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing/replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

Important: Check for a set/coast switch stuck in the engage position or the signal circuit is shorted to voltage.

Using Freeze Frame/Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame/Failure Records data can aid in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also aid determining how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

2. This step determines if the Set/Coast signal circuit is shorted to voltage.
3. This step determines if the TAC module or switch is at fault.
4. Check for a set/coast switch stuck in the engaged position or for the signal circuit for being shorted to voltage.
6. This DTC will not report a pass. The scan tool status for this DTC will never report a pass. The scan tool will only display when the diagnostic fails. The repair is not complete if the scan tool indicates that the diagnostic ran and failed.