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 Failure 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. |
| • | The 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.
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This step determines if the Set/Coast signal circuit is shorted to voltage.
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This step determines if the TAC module or the switch is at fault.
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Inspect for a set/coast switch stuck in the engaged position or for the signal circuit shorted to voltage.
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This DTC will not report a pass. The scan tool status for this DTC will never report a pass. The scan tool will only indicate the DTC when the diagnostic fails. The repair is not complete if the scan tool indicates that the diagnostic ran and failed.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Does scan tool indicate the Cruise Set/Coast switch ON? | -- | Go to Diagnostic Aids | ||
Does the test lamp illuminate? | -- | |||
Repair the short to voltage on the Set/Coast switch signal circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | -- | ||
5 | Replace the TAC module. Refer to Accelerator Pedal Replacement . Did you complete the repair? | -- | -- | |
Does the DTC reset? | -- | |||
7 | Does the scan tool indicated any DTCs set that you have not diagnosed? | -- | Go to the Applicable DTC Table | System OK |
