Diagnostic Instructions
DTC Descriptor
DTC P0068: Throttle Body Airflow Performance
Circuit/System Description
The engine control module (ECM) compares actual airflow based on throttle position (TP) and manifold absolute pressure (MAP) sensor to a calculated airflow.
Conditions for Running the DTC
| • | DTCs P0106, P0107, P0108, P0110, P0111, and P0112 are not set. |
| • | The DTC runs continuously when the above conditions are met. |
Conditions for Setting the DTC
The ECM detects that the actual airflow rate is greater than the calculated airflow.
Action Taken When the DTC Sets
| • | DTC P0068 is a Type A DTC. |
| • | The ECM commands the TAC system to operate in a Reduced Engine Power mode. |
| • | The ECM commands the reduced engine power indicator ON. |
| • | DTCs P2106 and P2110 will set. |
Conditions for Clearing the DTC
DTC P0068 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
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Important: In extreme cold weather conditions ice may form in the vacuum source to the MAP sensor and may set a DTC. Inspect the MAP sensor and the vacuum source for ice, moisture, or other restrictions.
- Ignition ON, observe the scan tool manifold absolute pressure (MAP) sensor pressure parameter and compare the reading on the scan tool to the barometric pressure table. Refer to
Altitude Versus Barometric Pressure.
- Engine running, observe the scan tool MAP Sensor parameter. The reading should be between 32-42 kPa.
- 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.
Circuit/System Testing
- Verify none of the following conditions exist:
| • | The air intake duct system for loose connecting clamps, cracks, or other damage |
| • | The air intake duct system for being collapsed or restricted possibly by a restricted air filter |
| • | A damaged throttle body blade or shaft |
| • | Splits, kinks, or improper connections at the vacuum hoses |
| • | Vacuum leaks at the intake manifold, throttle body, and injector O-rings |
- If all conditions test normal, test the engine for a mechanical condition. Refer to
Symptoms - Engine Mechanical.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
