P0068: MAP/MAF - Throttle Position Correlation

What does P0068 mean?

The engine control module compares the air quantity measured by the manifold pressure and/or mass air flow sensor with the quantity the throttle position leads it to expect. P0068 is set when they do not match, typically because more air arrives than the nearly closed throttle allows, i.e. an air leak behind the throttle, or because the throttle body is dirty or a sensor reads wrong. On engines with electronic throttle this check protects throttle control, so the engine often goes into reduced power. Each sensor can be electrically fine on its own; regulations require such plausibility checks for input sensors with a code of their own.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Reduced power mode
• Rough or unstable idle
• Jerking

Common causes

• High Air leak behind the throttle: intake manifold, vacuum or MAP hoses
• High Throttle body dirty
• Medium Mass air flow or manifold pressure sensor faulty
• Medium Engine control software (manufacturer updates exist)
• Low Camshaft timing out of position

Likelihood is a general estimate across vehicles; your make and model may differ.