GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Aveo 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P2104, P2105, P2106, or P2110

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 Descriptors

DTC P2104: Throttle Actuator Control (TAC) System - Forced Engine Idle

DTC P2105: Throttle Actuator Control (TAC) System - Forced Engine Shutdown

DTC P2106: Throttle Control System Performance - Throttle Limitation Active

DTC P2110: Throttle Actuator Control (TAC) System - Forced Limited Engine Speed

Circuit/System Description

DTC P2104, P2105, P2106, and P2110 indicate that a throttle actuator control (TAC) DTC is set that causes the engine control module (ECM) to command one of the following Reduced Power modes:

    • Forced engine idle
    • Forced engine shutdown
    • Throttle limitation
    • Limited engine speed

Conditions for Running the DTC

The ignition is ON or the engine is running.

Conditions for Setting the DTC

A failure with the TAC system is present.

Action Taken When the DTC Sets

P2104, P2106, and P2110

    • DTC P2104, P2106, and P2110 are Type A DTCs.
    • The ECM commands the TAC system to operate in a Reduced Engine Power mode.
    • The ECM commands the reduced engine power indicator ON.

P2105

    • DTC P2105 is a Type B DTC.
    • Engine operation will be disabled.

Conditions for Clearing the DTC

DTC P2104, P2106, and P2110 are Type A DTCs. DTC P2105 is a Type B DTC.

Reference Information

Description and Operation

Throttle Actuator Control (TAC) System Description

Circuit/System Verification

    Important: 

       • A low battery condition while cranking the engine may cause DTC P2106 to set. Refer to Symptoms - Engine Electrical.
       • In extreme cold weather conditions ice may form in the vacuum source to the MAP sensor and may set a DTC. Inspect the MAP sensor and the vacuum source for ice, moisture, or other restrictions.

  1. Ignition ON, observe the scan tool MAP sensor data parameter. Engine running, verify the scan tool MAP sensor data parameter changes.
    2. ⇒If the MAP data parameter does not change, refer to DTC P0107 or P0108 for further diagnosis.
  2. Verify no vacuum leak exists.
    3. ⇒If a vacuum does exist, repair as necessary.
  3. DTCs P2104, P2105, P2106, and P2110 are informational DTCs. Correct the throttle actuator control (TAC) system DTCs that are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming