The engine control module (ECM) compares actual airflow based on throttle position (TP) and manifold absolute pressure (MAP) sensor to a calculated airflow.

The ECM detects that the actual airflow rate is greater than the calculated airflow.

DTC P0068 is a Type A DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

DTC Type Reference

Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Engine Control Module Scan Tool Information

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 MAP sensor pressure parameter and compare the reading on the scan tool to the barometric pressure table. Refer to Altitude Versus Barometric Pressure .

⇒	If the MAP sensor pressure is not within the range specified for your altitude, refer to DTC P0107 or P0108 .

2. Engine idling, observe the MAP Sensor parameter. The reading should be between 32-42 kPa.
3. If the MAP sensor pressure is not within the specified range, refer to DTC P0107 or P0108 .
4. Increase the engine speed slowly to 3,000 RPM, then back to idle while observing the scan tool MAF sensor g/s parameter. The scan tool MAF sensor g/s parameter should change smoothly and gradually as the engine speed is increased and returned to idle.

⇒	If the scan tool MAF sensor g/s parameter does not change smoothly and gradually as the engine speed is increased and returned to idle refer to DTC P0102 or P0103 .

5. 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.

1. 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

•	Missing, restricted, or leaking exhaust components

•	Vacuum leaks at the intake manifold, throttle body, and injector O-rings

⇒	If a condition exists, repair as necessary.

2. If all conditions test normal, test the engine for a mechanical condition.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Throttle Body Assembly Replacement