What Does P0068 Mean?
The ECM has detected a disagreement between the MAP (Manifold Absolute Pressure) or MAF (Mass Air Flow) sensor reading and the throttle position sensor reading. Under normal conditions, these values should correlate — higher throttle opening should produce higher airflow and corresponding changes in manifold pressure. This mismatch suggests one or more sensors are reading incorrectly, or there is an actual airflow problem. The driver may notice poor acceleration, hesitation, surging, or rough idle.
Common Causes
28%
Dirty or contaminated MAF sensor giving incorrect airflow readings
25%
Vacuum leak allowing unmetered air into the intake manifold
22%
Faulty throttle position sensor or throttle body with carbon buildup
15%
MAP sensor failure or clogged MAP sensor vacuum hose
10%
Restricted air filter or intake obstruction
Diagnostic Steps
1
Compare MAF and MAP sensor readings at idle and at 2500 RPM using live PID data. At idle, MAP should read 15-22 inHg vacuum; MAF should be 2-7 g/s for most 4-cylinder engines. Values outside these ranges point to the faulty sensor.
2
Monitor throttle position sensor — it should read 0-1% at closed throttle and increase smoothly to 100% at wide open. Any dead spots, jumps, or values that don't return to 0% indicate a TPS issue.
3
Perform a smoke test on the intake system to check for vacuum leaks. Even a small leak can cause enough unmetered air to create a MAP/MAF vs. TPS correlation issue.
4
Clean the MAF sensor with MAF-specific cleaner (never use carb cleaner or contact cleaner). A contaminated MAF hot wire reads low, causing the mismatch. Retest after cleaning.
5
Inspect the throttle body for carbon buildup. A restricted throttle bore reduces actual airflow below what the TPS position suggests, triggering a correlation fault. Clean with throttle body cleaner.
6
Check the MAP sensor vacuum hose (if equipped with a remote MAP sensor) for cracks, kinks, or disconnections.
Estimated Repair Cost
$50 - $500
Parts + labor, varies by vehicle and location
The ECM has detected a disagreement between the MAP (Manifold Absolute Pressure) or MAF (Mass Air Flow) sensor reading and the throttle position sensor reading. Under normal conditions, these values should correlate — higher throttle opening should produce higher airflow and corresponding changes in...
The most common cause of P0068 (MAP / MAF - Throttle Position Correlation) is: Dirty or contaminated MAF sensor giving incorrect airflow readings
Typical repair costs for P0068 range from $50 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle may exhibit hesitation or surging which could be dangerous in traffic. If the engine runs rough or stalls, avoid highway driving until diagnosed. The ECM may use incorrect fuel calculations, causing lean or rich conditions that can damage the catalytic converter. Diagnose and repair within 1-2 weeks.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0068 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Generic (SAE)
Recommended Tools
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