P0068: MAP/MAF – throttle position correlation
The air flow (MAF) or intake pressure (MAP) reading doesn’t match the throttle position: the engine gets more or less air than the throttle opening suggests.
Updated
What P0068 means
The engine computer knows how far the throttle is open, and measures the air going in with an air flow (MAF) sensor, an intake pressure (MAP) sensor, or both. The two should fit: a wider throttle means more air.
P0068 means they don’t. Either air gets in behind the throttle (a leak), less air comes through than expected (a dirty throttle body or a blocked air filter), or one of the sensors gives a wrong reading.
Read My Car shows the throttle position, air flow and intake pressure under Live data, if your car reports them.
Can I keep driving?
Drive gently
Drive gently and have it checked soon. The engine can lose power, hesitate or stall, so avoid motorways and overtaking until it’s fixed. If the engine stalls or runs very rough, don’t drive on: have it checked first.
General guidance based on the code alone, not on the car’s actual condition. If in doubt, stop and ask a mechanic.
On many cars this code comes with less power, hesitation or a rough idle, and the engine can stall. A large air leak can also set a lean code (P0171).
Symptoms
- Hesitation or less power when accelerating.
- A rough or uneven idle, or stalling.
- Hard starting on some cars.
- Higher fuel use.
Common causes
- Vacuum or intake air leak. The most frequent cause: a cracked or loose hose, or a leaking intake or throttle body gasket, lets in air behind the throttle.
- Dirty throttle body. Carbon around the throttle plate lets less air through than its position suggests.
- Faulty air flow (MAF) or intake pressure (MAP) sensor. Check the hose to the MAP sensor too, where it has one: a blocked or loose hose distorts the reading.
- Faulty throttle position sensor. If it misreports the throttle opening, the air no longer matches it.
Typical fixes
- Check the air filter, and the intake ducting and hoses for splits and loose clamps.
- Look and listen for vacuum leaks with the engine idling.
- Have the throttle body checked for carbon and cleaned if needed. Some cars need a throttle relearn afterwards, with a tool for the make.
- Compare the throttle position, air flow and intake pressure in live data, and have the sensors tested if no leak is found.
Questions
Can I drive with P0068?
Gently, and have it checked soon. The engine can lose power, hesitate or stall, so avoid motorways and overtaking until it’s fixed. If it stalls or runs very rough, don’t drive on: have it checked first.
Can a vacuum leak cause P0068?
Yes, it’s one of the most common causes: air that gets in behind the throttle doesn’t fit the throttle opening. A lean code (P0171) stored at the same time points the same way.