• 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 P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0335, P0336 = Not set
• Engine Speed=500 to 6,800 RPM
• Engine Coolant Temperature=−7 to 126°C (19 to 259°F)
• Intake Air Temperature=−20 to 125°C (−4 to 257°F)

Frequency the DTC runs=ContinuouslyAfter the running conditions are met

• DTC P06A3 = Not set
• Ignition=OnorEngine=Running
• Run/Crank Circuit Voltage=Greater than 6.41 V
• Reduced Engine Power=Deactivated

Frequency the DTC runs=ContinuouslyAfter the running conditions are met

• DTC P06A3 = Not set
• Ignition=OnorEngine=Running
• Run/Crank Circuit Voltage=Greater than 6.41 V
• Reduced Engine Power=Deactivated

Frequency the DTC runs=ContinuouslyAfter the running conditions are met—Greater than 1 s

• DTC P0122, P0123, P0222, P0223, P06A3 = Not set
• Ignition=OnorEngine=Running
• Run/Crank Circuit Voltage=Greater than 6.41 V
• Reduced Engine Power=Deactivated

Frequency the DTC runs=ContinuouslyAfter the running conditions are met

Throttle Position Sensor 1=Signal Stuck In Range—For greater than 1 s

Throttle Position Sensor 1=Less than 0.33 V—For greater than 1 s

Throttle Position Sensor 1=Greater than 4.75 V—For greater than 1 s

Throttle Position Sensor 2=Less than 0.25 V—For greater than 1 s

Throttle Position Sensor 2=Greater than 4.59 V—For greater than 1 s

Serial Data circuit=Less than 0.5 V—For greater than 1 s

Serial Data circuit=Greater than 4.1 V—For greater than 1 s

Serial Data circuit=Message Counter Incorrect/Too Many Pulses/Too Few Pulses

• Throttle Position Sensor 1, 2=Not within 7-10% of each other—For greater than 1 s
• Throttle Position Sensor 1, 2 Learned MinimumGreater than 5%—5 V Reference

DTCs listed in the DTC Descriptor category=Type A DTC—Exceptions listed below

DTC P0121=Type B DTC

• Reduced Engine Power=Active
• P16 Instrument Cluster=Reduced Engine Power
• Under certain conditions, the control module commands the engine Off.

DTCs listed in the DTC Descriptor category=Type A DTC—Exceptions listed below

DTC P0121=Type B DTC

• A high resistance condition on the component circuits may cause the DTC to set.
• If the accelerator pedal is pressed all the way down, the throttle blade angle and the scan tool Throttle Position angle parameter will only go to an angle less than 40%.
• Under cold start conditions, it might happen briefly that the desired and the actual throttle blade position do not match.

Engine Controls Schematics

Master Electrical Component List

• 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 / Vehicle » In Service Mode
2. Verify DTC P0601-P0606, P06A3, P16F3 is not set
• If any of the DTCs are set

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

• If none of the DTCs are set
3. Verify the scan tool parameter:Throttle Body Idle Air Flow Compensation=Less than 90%
• If 90% or greater

  Refer to:Throttle Body Cleaning

• If less than 90%
4. Verify DTC P0122, P0123, P0222, P0223, P16A0, P16A1, P16A2, P2135 is not set
• If only DTC P0122, P0123, P0222, P0223, P2135 is set

  Test or replace the component:Q38 Throttle Body

• If DTC P16A0, P16A1, P016A2 and one or more of the DTCs P0122, P0123, P0222, P0223, P2135 is set

  Refer to: Circuit/System Testing

• If none of the DTCs are set
5. Perform the scan tool control function:Throttle Sweep»Start

   Verify the scan tool parameter:Throttle Position Sensors 1 and 2=Agree

• If not the specified state

  Test or replace the component:Q38 Throttle Body

• If the specified state
6. Verify the scan tool parameter:
• Manifold Absolute Pressure Sensor=The value should be within the range listed in the table:Altitude Versus Barometric Pressure
• Boost Pressure Sensor=The value should be within the range listed in the table:Altitude Versus Barometric Pressure
• If not in the specified range
• {Manifold Absolute Pressure Sensor}Refer to:DTC P0106, P0107, or P0108
• {Boost Pressure Sensor}Refer to:DTC P0236, P0237, or P0238
• If in the specified range
7. Engine»Running
8. Verify the scan tool parameter:
• Manifold Absolute Pressure Sensor=26 to 52 kPa (3.8 to 7.5 PSI)@Idle Speed
• Manifold Absolute Pressure Sensor=The value should change with accelerator pedal input.
• If not in the specified range or does not change

  Refer to:DTC P0106, P0107, or P0108

• If in the specified range and changes
9. Verify the scan tool parameter:Boost Pressure Sensor=The value should change with accelerator pedal input.
• If the value does not change

  Refer to:DTC P0236, P0237, or P0238

• If the value changes
10. Increase the engine speed slowly to 3k RPM and then back to idle.
11. Perform the scan tool function:Review Stored Data
12. Observe the scan tool parameter frame by frame with a scan tool:MAF Sensor

    Verify the scan tool parameter:MAF Sensor=The value should not spike or drop out.

• If the value spikes or drops out

  Refer to:DTC P0102 or P0103

• If the value does not spike or drop out
13. 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.

    Verify the DTC does not set.

• If the DTC sets

  Refer to: Circuit/System Testing

• If the DTC does not set
14. All OK.

Note:

• Disconnecting the component electrical connector causes additional DTCs to set.
• It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

1. Ignition/Vehicle & All vehicle systems » Off
2. Disconnect the appropriate electrical connector:Q38 Throttle Body
3. Test for less than 5 Ω between the test points:Low Reference circuit terminal 4&Ground
• If 5 Ω or greater
1. Disconnect the electrical connector:K20 Engine Control Module
2. Test for less than 2 Ω between the test points:Low Reference circuit terminal 4@Component harness&The other end of the circuit@Control module harness
• If 2 Ω or greater » Repair the open/high resistance in the circuit.
• If less than 2 Ω » Replace the component:K20 Engine Control Module
• If less than 5 Ω
4. Ignition » On / Vehicle » In Service Mode
5. Test for 4.8 to 5.2 V between the test points:5 V Reference circuit terminal 5&Ground
• If less than 4.8 V
1. Ignition/Vehicle » Off
2. Disconnect the electrical connector:K20 Engine Control Module
3. Test for infinite resistance between the test points:5 V Reference circuit terminal 5@Component harness&Ground
• If less than infinite resistance » Repair the short to ground on the circuit.
• If infinite resistance
4. Test for less than 2 Ω between the test points:5 V Reference circuit terminal 5@Component harness&The other end of the circuit@Control module harness
• If 2 Ω or greater » Repair the open/high resistance in the circuit.
• If less than 2 Ω » Replace the component:K20 Engine Control Module
• If greater than 5.2 V
1. Ignition/Vehicle » Off
2. Disconnect the electrical connector:K20 Engine Control Module
3. Ignition » On / Vehicle » In Service Mode
4. Test for less than 1 V between the test points:5 V Reference circuit terminal 5@Component harness&Ground
• If 1 V or greater » Repair the short to voltage on the circuit.
• If less than 1 V » Replace the component:K20 Engine Control Module
• If between 4.8 and 5.2 V
6. Test for 4.8 to 5.2 V between the test points:Serial Data circuit terminal 3&Ground
• If less than 4.8 V
1. Ignition/Vehicle » Off
2. Disconnect the electrical connector:K20 Engine Control Module
3. Test for infinite resistance between the test points:Serial Data circuit terminal 3@Component harness&Ground
• If less than infinite resistance » Repair the short to ground on the circuit.
• If infinite resistance
4. Test for less than 2 Ω between the test points:Serial Data circuit terminal 3The other end of the circuit
• If 2 Ω or greater » Repair the open/high resistance in the circuit.
• If less than 2 Ω » Replace the component:K20 Engine Control Module
• If greater than 5.2 V
1. Ignition/Vehicle » Off
2. Disconnect the electrical connector:K20 Engine Control Module
3. Ignition » On / Vehicle » In Service Mode
4. Test for less than 1 V between the test points:Serial Data circuit terminal 3@Component harness&Ground
• If 1 V or greater » Repair the short to voltage on the circuit.
• If less than 1 V » Replace the component:K20 Engine Control Module
• If between 4.8 and 5.2 V
7. Test or replace the component:Q38 Throttle Body

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

• Throttle Body Assembly Replacement—Q38 Throttle Body
• For control module replacement, programming, and setup refer to:Control Module References