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 Descriptors

DTC P2176: Minimum Throttle Position Not Learned

Circuit/System Description

The engine control module (ECM) controls the throttle valve by applying a varying voltage to the throttle actuator control (TAC) motor. The ECM monitors the actual throttle valve position using throttle position sensor 1 and 2.

Conditions for Running the DTC

    • The engine speed is less than 40 RPM.
    • The vehicle speed is 0 km/h (0 mph).
    • The engine coolant temperature (ECT) is between 5-101°C (41-214°F).
    • The intake air temperature (IAT) is between 5-144°C (41-291°F).
    • The accelerator pedal position (APP) sensor angle is less than 15 percent.
    • The ignition voltage is greater than 10 volts.
    • DTC P2176 runs once per ignition cycle, when the ignition is ON and the above conditions are met for greater than 1 second.

Conditions for Setting the DTC

    • The ECM detects that the TP sensor 1 voltage is not between 4.12-4.55 V after the throttle learn procedure, with the throttle at rest.
    • The ECM detects that the TP sensor 2 voltage is not between 0.34-0.99 V after the throttle learn procedure, with the throttle at rest.
    • The minimum throttle position is not learned after an ECM replacement.
    • Either condition exists fro greater than 1 second, or a cumulative 10 seconds.

Action Taken When the DTC Sets

DTC  P2176 is a Type A DTC.

Conditions for Clearing the DTC

DTC P2176 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. Ignition ON, rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release the pedal. Repeat the procedure several times. Observe the DTC information with a scan tool. Verify that DTC P0121, P0122, P0123, P0221, P0222, P0223, P0638, or P2101 do not set.
  2. If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
  3. DTC P2176 is an informational DTC. Perform the throttle learn procedure, refer to Throttle Learn.
  4. If DTC P2176 resets after performing the throttle learn procedure, replace the Q38 throttle body.
  5. 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.

Throttle Body Assembly Replacement