• 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 P1682 = Not set
• Ignition Voltage=Greater than 6.4 V
• Throttle Position Learn=Not Activated

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

• DTC P1682 = Not set
• Ignition Voltage=Greater than 6.4 V
• Throttle Position Learn=Not Activated
• Engine=Running

• Ignition Voltage=Greater than 6.4 V
• Throttle Position Learn=Active

• Ignition Voltage=Greater than 6.4 V
• Reduced Engine Power=Active

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

• DTC P0122, P0123, P0222, P0223, P06A3 = Not set
• Ignition Voltage=Greater than 6.4 V
• Engine=Not Running

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

• Ignition Voltage=Greater than 6.4 V
• Throttle Position Learn=Active

Frequency the DTC runs=Continuously—After the running conditions are met—For greater than 2 s

The following parameters are not within 2% of each other:

• Desired Throttle Position
• Throttle Position

The following parameters are not within 10% of each other:

• Desired Throttle Position
• Throttle Position

• Throttle Position Learn=Active
• Throttle Position=Greater than 38%

• Throttle Position Learn=Active
• Throttle Position=Greater than 50%

The throttle blade has not reached the closed position after the engine has been turned off.

Minimum Throttle Position Not Learned=Exceeded Number of Attempts

DTC P1516=Type B DTC

DTC P2101, P2176=Type A DTC

DTC P2119=Type C DTC

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

• DTC P1516=Type B DTC
• DTC P2101, P2176=Type A DTC
• DTC P2119=Type C DTC

• A high resistance condition on the throttle position and throttle actuator control circuits could cause a DTC to set.
• A weak battery may cause this DTC to set.
• If the throttle blade becomes stuck, a DTC will set. Depending on the position of the throttle blade, the engine control module (ECM) may enter Engine Shutdown Mode. The ECM will disable fuel and de-energize the throttle actuator. If the condition remains present during the next ignition cycle, the ECM may disable engine cranking. Inspect the throttle body assembly for a stuck throttle blade if a throttle actuator DTC is current and the engine won't crank.
• Inspect for a condition in which the throttle blade may have been held open. For example, ice may have formed in the throttle bore causing the throttle blade not to close.
• 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 P0068, P0121, P0122, P0123, P0222, P0223, P0562, P06A3, P0606, P0607, P0621, P0622, P16A0-P16A2, P2135, U0606, U0607 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. Clear the DTCs.
5. Ignition/Vehicle » Off
6. Ignition » On / Vehicle » In Service Mode
7. Perform the scan tool control function:Throttle Sweep»Start

   Verify the scan tool parameter:TAC Motor=Enabled

• If not the specified state

  Refer to: Circuit/System Testing

• If the specified state
8. Verify the scan tool parameter:TAC Motor=Enabled

   Perform the action while monitoring the parameter:

• Wiggle the harness and connector(s):Q38 Throttle Body
• Wiggle the harness and connector(s):X2@K20 Engine Control Module
• If not the specified state

  Repair as necessary » Wiring / Terminal(s) / Electrical Connector(s)

• If the specified state
9. 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
10. All OK.

1. Ignition/Vehicle » Off
2. Verify the following conditions do not exist:

Warning: Turn OFF the ignition before inserting fingers into the throttle bore. Unexpected movement of the throttle blade could cause personal injury.

• The throttle blade has not reached the closed position after the engine has been turned off.
• The throttle blade is not closed by the spring.
• The throttle blade is binding in open or closed position.
• If a condition exists

  Replace the component:Q38 Throttle Body

• If no condition exists

Note: Disconnecting the component electrical connector causes additional DTCs to set.

3. Disconnect the electrical connector:Q38 Throttle Body
4. Ignition » On / Vehicle » In Service Mode
5. Test for 5 to 8 V between the test points:
• Control circuit terminal 1/A&Ground
• Control circuit terminal 2/B&Ground
• If less than 5 V
1. Ignition/Vehicle » Off
2. Disconnect the electrical connector:X2@K20 Engine Control Module
3. Test for infinite resistance between the test points:
• Control circuit terminal 1/A@Component harness&Ground
• Control circuit terminal 2/B@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:
• Control circuit terminal 1/A@Component harness&The other end of the circuit@Control module harness
• Control circuit terminal 2/B@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 8 V
1. Ignition/Vehicle » Off
2. Disconnect the electrical connector:X2@K20 Engine Control Module
3. Ignition » On / Vehicle » In Service Mode
4. Test for less than 1 V between the test points:
• Control circuit terminal 1/A@Component harness&Ground
• Control circuit terminal 2/B@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 5 and 8 V
6. Ignition/Vehicle » Off
7. Disconnect the electrical connector:X2@K20 Engine Control Module
8. Test for less than 2 Ω between the test points:
• Control circuit terminal 1/A@Component harness&The other end of the circuit@Control module harness
• Control circuit terminal 2/B@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
9. Ignition OFF, Set the DMM to the 40 V scale, select the Min/Max Recording Mode, and set the Peak Min/Max response time to 1 ms.

Note:

• The ignition must be OFF and the ECM completely powered down before testing each circuit or a lower voltage will be recorded. It may take up to 2 min for all vehicle systems to power down.
• The DMM Min/Max Recording Mode and the response time of 1 ms must be reset after testing each circuit or a lower voltage will be recorded.

10. Verify the Max voltage is within 3 V of B+ while using DMM Min/Max Recording Mode function on each control circuit listed below as the ignition is turned ON.
• Control circuit terminal 1/A@Component harness&Ground
• Control circuit terminal 2/B@Component harness&Ground
• If not within 3 V of the battery voltage

  Test or replace the component:K20 Engine Control Module

• If within 3 V of the battery voltage
11. Test or replace the component:Q38 Throttle Body

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

• Throttle Body Assembly Replacement
• For the system learn/reset procedure refer to:Throttle Body Idle Air Flow Compensation Reset
• For control module replacement, programming, and setup refer to:Control Module References