GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The throttle body assembly contains the following components:

    • The throttle blade
    • The throttle actuator motor
    • The throttle position (TP) sensor 1 and TP sensor 2
    • The throttle actuator control (TAC) module

The TAC system monitors throttle position. The throttle blade is spring loaded in both directions and at rest is slightly open. When throttle blade is not driven in either direction it returns to this position. If the TAC module determines that the throttle blade has not returned to the correct de-energized position the TAC module sends a message to the powertrain control module (PCM) across serial data and DTC P2119 sets.

Conditions for Running the DTC

    • DTC P1518 is not set.
    • The ignition is ON and the engine is OFF.
    • The ignition voltage is more than 8.5 volts.
    • The system is not in Battery Saver mode.

Conditions for Setting the DTC

The TAC module detects that the throttle blade has not returned to the correct de-energized position.

Action Taken When the DTC Sets

    • The control module stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
    • The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC

    • A current DTC Last Test Failed clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
    • Clear the DTC with a scan tool.

Diagnostic Aids

Inspect for mechanical conditions or for binding that may be temperature related. components may not move freely in extreme heat or cold due to the presence of contaminants or ice formation.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Powertrain Control Module Connector End Views and Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check-Engine Controls?

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Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Is DTC P1516, P2101 also set?

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Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

  1. Turn OFF the ignition for 15 seconds.
  2. Turn ON the ignition, with the engine OFF.
  3. Allow the pedal to rest at stop for 30 seconds.
  4. Observe the indicated throttle position parameter with a scan tool.

Does the scan tool indicate throttle position within the specified range?

17-27%

Go to Step 6

Go to Step 4

4

Remove the throttle body assembly. Refer to Throttle Body Assembly Replacement .

Did you find any obstructions preventing the throttle blade from returning to the default position?

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Go to Step 5

Go to Step 6

5

Remove the obstruction.

Did you complete the repair?

--

Go to Step 7

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6

Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement .

Did you complete the replacement?

--

Go to Step 7

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7

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

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Go to Step 2

Go to Step 8

8

Important: Be aware that repairing 1 individual condition may correct more than 1 DTC.

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

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Go to Diagnostic Trouble Code (DTC) List

System OK