GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    •  Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    •  Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P2101: Control Module Throttle Actuator Position Performance

Circuit/System Description

The commanded throttle position is compared to the actual throttle position based on the accelerator pedal position and possibly other limiting factors. Both values should be within a calibrated range of each other. The powertrain control module (PCM) continuously monitors the commanded and the actual throttle positions. If the commanded and the actual positions are not within a calibrated range of each other, DTC P2101 sets.

Conditions for Running the DTC

    • The ignition is in the Crank or Run position.
    • The system voltage is more than 5.23 volts.
    • The system is not in Battery Saver mode.
    • The communication between the TAC module and the PCM must be valid.
    • The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTC

    • The TAC module detects the commanded and the actual throttle positions are not within a calibrated range of each other.
        OR
    • The TAC module or the PCM can not determine the throttle position.

Action Taken When the DTC Sets

    • DTC P2101 is a Type A DTC.
    • The control module commands the TAC system to operate in Reduced Engine Power mode.

Conditions for Clearing the DTC

DTC P2101 is a Type A DTC.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Throttle Actuator Control (TAC) System Description

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. If DTC P2108 is also set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  2. If DTC U0107 only is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  3. Ignition OFF for 30 seconds.
  4. Ignition ON, observe the TP Sensor 1 and TP Sensor 2 parameters while moving the accelerator pedal to the fully applied position, and back to the at-rest position. The TP Sensor parameters should increase to 100 percent as the accelerator pedal is moved to the fully applied position, and back tot he at-rest position as the accelerator pedal is released.
  5. Operate the vehicle within the Conditions for Running the DTC, or within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

Test the ETC ignition 1 voltage circuit for proper continuity.

If the circuit has proper continuity, replace the throttle body assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Throttle Body Assembly Replacement