• Perform the Diagnostic System Check prior to using this diagnostic procedure:Diagnostic System Check - Vehicle
• Review the description of Strategy Based Diagnosis:Strategy Based Diagnosis
• An overview of each diagnostic category can be found here:Diagnostic Procedure Instructions

For an overview of the component/system, refer to:Throttle Actuator Control (TAC) System Description

• DTC P0068, P0101, P0102, P0103, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0172, P0174, P0175, P0222, P0223, P0261, P0262, P0264, P0265, P0267, P0268. P0270, P0271, P0273, P0274, P0276, P0277, P0300–P0306, P0351–P0356, P0461–P0464, P0496, P0627, P0628, P0629, P0722, P1516, P2066–P2068 = Not set
• Barometric PressureGreater than 70 kPa (10 PSI)
• Engine Coolant TemperatureGreater than 60°C (140°F)
• Engine Run TimeGreater than 60 s
• Ignition VoltageBetween Lambda 11 and 32V
• TransmissionNot BusyShifting from GearorShifting to Gear
• Torque Converter Clutch=Inactive
• Intake Air TemperatureGreater than -20°C (-4°F)
• Vehicle SpeedLess than 3 km/h (2 MPH)
• Engine speed varies less than +/-25 RPM
• EngineIdlingGreater than 5 s

Frequency the DTC runs=Continuously—After the running conditions are met

Engine Speed=94 RPMLess than desiredEngine SpeedFor greater than 10 s

Engine Speed=188 RPMGreater than desiredEngine SpeedFor greater than 10 s

DTCs listed in the DTC Descriptor category=Type B DTC

DTCs listed in the DTC Descriptor category=Type B DTC

Engine Controls Schematics 

Master Electrical Component List

Throttle Actuator Control (TAC) System Description

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

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Control Module References

1. Ignition On
2. Verify no other DTCs are set.
• If any other DTCs are set

  Refer to:Diagnostic Trouble Code (DTC) List - Vehicle

• If no other DTCs are set
3. Verify the scan tool parameter:Throttle Body Idle Air Flow CompensationLess than 90%
• If greater than 90%

  Refer to:Throttle Body Inspection and Cleaning

• If less than 90%
4. Engine » Idling — At normal operating temperature
5. Verify the scan tool parameter:Engine Speed=−100 to +200 RPM of the Desired Idle Speed
• If a condition existsEngine SpeedLess than desired−100 to +200 RPM of the Desired Idle Speed

  Refer to: Circuit/System Testing

• If a condition existsEngine SpeedGreater than desired−100 to +200 RPM of the Desired Idle Speed

  Refer to: Circuit/System Testing

• If a condition existsEngine Speed200 RPMLess than desired
6. 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 data.
7. Verify the DTC does not set.
• If the DTC sets

  Refer to: Circuit/System Testing

• If the DTC does not set
8. All OK.

1. Verify the following conditions do not exist:
• The engine speed is limited.Mechanical Condition
• Exhaust System—Restricted
• Parasitic LoadOnEngine
• If a condition exists

  Repair as necessary

• If no conditions exist
2. All OK.

1. Verify the following conditions do not exist:
• Vacuum leak
• Throttle Plate at Closed PositionIncorrect
• Verify the correct operation:Positive Crankcase Ventilation SystemRefer to:Crankcase Ventilation System Inspection/Diagnosis
• If a condition exists

  Repair as necessary

• If no conditions exist
2. All OK.

Perform the Diagnostic Repair Verification after completing the repair:Diagnostic Repair Verification

Throttle Body Assembly Replacement—Q38 Throttle Body