P0068 – MAP/MAF Throttle Position Correlation
The P0068 diagnostic trouble code indicates that the Engine Control Module (ECM) has detected an incorrect correlation between the Throttle Position (TP), Manifold Absolute Pressure (MAP), and Mass Air Flow (MAF) sensor signals.
The ECM continuously compares these sensor readings to calculate engine load. If one or more signals do not agree with the expected airflow entering the engine, the ECM stores the P0068 code and illuminates the Check Engine Light.
Common Symptoms
- Check Engine Light ON
- Rough idle
- Poor acceleration
- Reduced engine power
- Engine hesitation or stalling
- Increased fuel consumption
Common Causes
- Dirty or faulty MAF sensor
- Faulty MAP sensor
- Faulty throttle body or throttle position sensor
- Vacuum leak in the intake system
- Air intake leak after the MAF sensor
- Damaged wiring or poor electrical connections
- Rarely, a faulty ECM
Basic Diagnosis
Inspect the air intake system for vacuum leaks, check the air duct between the MAF sensor and throttle body, clean the MAF sensor using a dedicated MAF cleaner, compare MAP, MAF, and throttle position data with a scan tool, and inspect the wiring and connectors for damage or corrosion.
Diagnostic Note: The expected correlation between the MAP, MAF, and throttle position sensors varies by engine design and manufacturer. Always compare live data against the specifications for the specific vehicle before replacing any components.