P0068
DTC P0068
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Strategy Based Diagnosis Strategy Based Diagnosis
* Diagnostic Procedure Instructions Diagnostic Procedure 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
* The engine is running.
* 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 more 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 (w/Throttle Actuator Controls) Electrical DiagramsEngine Controls Schematics (w/o Throttle Actuator Control) Electrical Diagrams
Connector End View Reference
* Engine Control Module Connector End Views (w/ Throttle Actuator Control) Engine Control Module Connector End Views (w/ Throttle Actuator Control)Engine Control Module Connector End Views (w/o Throttle Actuator Control) Engine Control Module Connector End Views (w/o Throttle Actuator Control)
* Engine Controls Connector End Views (w/ Throttle Actuator Control) Engine Controls Connector End Views (w/ Throttle Actuator Control)Engine Controls Connector End Views (w/o Throttle Actuator Control) Engine Controls Connector End Views (w/o Throttle Actuator Control)
Description and Operation
Throttle Actuator Control (TAC) System Description Throttle Actuator Control (TAC) System Description
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
* Scan Tool Data List (w/ Throttle Actuator Control) Scan Tool Data List (w/ Throttle Actuator Control)Scan Tool Data List (w/o Throttle Actuator Control) Scan Tool Data List (w/o Throttle Actuator Control)
* Scan Tool Data Definitions (w/ Throttle Actuator Control) Scan Tool Data Definitions (w/ Throttle Actuator Control)Scan Tool Data Definitions (w/o Throttle Actuator Control) Scan Tool Data Definitions (w/o Throttle Actuator Control)
* Scan Tool Output Controls (w/ Throttle Actuator Control) Scan Tool Output Controls (w/ Throttle Actuator Control)Scan Tool Output Controls (w/o Throttle Actuator Control) Scan Tool Output Controls (w/o Throttle Actuator Control)
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.
1. Ignition ON, observe the 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 Altitude Versus Barometric Pressure.
• If the MAP sensor pressure is not within the range specified for your altitude, refer to DTC P0107 or P0108 P0107.
2. Start the engine, observe the MAP Sensor parameter. The reading should be between 32-42 kPa.
3. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.
Circuit/System Testing
1. Verify that 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
* Missing, restricted, or leaking exhaust components-Refer to Symptoms - Engine Exhaust Symptoms - Engine Exhaust.
* Vacuum leaks at the intake manifold, throttle body, and injector O-rings
2. If all conditions test normal, test the engine for a mechanical condition. Refer to Symptoms - Engine Mechanical Symptoms - Engine Mechanical.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Throttle Body Assembly Replacement Removal and Replacement
* Air Cleaner Assembly Replacement Service and Repair