GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Omega VE 🢒 DTC 🢒 DTC P0068

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category

DTC Descriptors

DTC P0068: MAP/MAF - Throttle Position Correlation

Circuit/System Description

The engine control module (ECM) uses the following information to calculate an expected airflow rate:

    • The throttle position (TP) sensor.
    • The manifold absolute pressure (MAP) sensor.
    • The intake air temperature (IAT) sensor.
    • The engine RPM.

Conditions for Running the DTC
    • DTCs P0641, P0651, P1516, P2101 or P2119 are not set.
    • The engine is running.
    • DTC P0068 runs continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the throttle position and the indicated engine load do not correspond with the expected load and throttle position for less than 1 second.

Action Taken when the DTC Sets

DTC  P0068 is a type A DTC.

Conditions for Clearing the MIL/DTC

DTC  P0068 is a type A DTC.

Reference Information

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References

Circuit/System Testing
  1. Inspect for the following conditions:
    2. • Vacuum hoses for splits, kinks and correct connections as shown on Vehicle Emission Control Information label.
    • Inspect thoroughly for any type of leak or restriction.
    • Air leaks at throttle body mounting area and intake manifold sealing surfaces.
  2. Inspect the throttle body for the following conditions:
    3. • Loose or damaged throttle blade.
    • Broken throttle shaft.
    • Any throttle body damage.
    ⇒If any of these conditions exist, replace the throttle body assembly.
  3. Using a scan tool allow the engine to reach normal operating temperature. Observe the MAP and MAF Sensor parameters.
  4. Take a snapshot of the engine data list while performing the actions listed below.
    5. • Idle the engine.
    • Increase the engine speed slowly to 3,000 RPM, then back to idle.
    • Exit from the snapshot and review the data.
    • Observe the MAP/MAF/TP sensor parameters frame by frame. The MAP/MAF/TP sensor parameters should change smoothly and gradually as the engine speed is increased and is returned to idle.
         ⇒If the MAP/MAF/TP sensor parameters do not change smoothly and gradually as the engine speed is increased and is returned to idle, identify the senor at fault and replace the appropriate sensor.

Repair Instructions

Perform the Diagnostic Repair Verification.

    •  Throttle Body Assembly Replacement
    •  Engine Control Module Replacement for engine control module replacement, setup and programming.