Powertrain, generic · Fuel and air metering, auxiliary emission controls

P0068 MAP/MAF - Throttle Position Correlation

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

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.

Likely causes

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

Symptoms

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

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–300
Time0.5–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

throttle bodymass air flow sensormanifold absolute pressure sensorthrottle position sensorintake manifold

Related codes

P0101P0106P0121P2135P006A

References: law.cornell.edu, gsi.ext.gm.com, newtonnet.co.uk, saabwisonline.com.