P112F

What the Code Means

P112F is an air-mass plausibility error. The engine control unit calculates that more or less air is entering the intake than the current throttle position should allow. The cause is almost always an unmetered air leak.

The code belongs to the same fault path as 101F01 and 28A0: on the N55 all three codes often set together because they describe the same air-mass monitoring logic.

Typical causes:

• cracked or loose hoses, charge pipes;
• valve cover vacuum reservoir seals;
• carbon buildup on the throttle body;
• faulty MAF or MAP sensors;
• wiring and connector problems that cause communication faults with these sensors.

Symptoms

The symptoms in the source are described for code 101F01, which belongs to the same fault path as P112F:

• poor acceleration;
• rough idle;
• Check Engine light on;
• hissing sound that points to an air leak.

Diagnosis and Repair

1. Check all hoses for visible cracks and damage; inspect the connections around the intake manifold and throttle body.
2. Run a smoke test with a smoke machine to find hard-to-spot leaks in the charge pipes and valve cover seals; check the connections and their tightness.
3. Replace damaged hoses and make sure the intake manifold is sealed.
4. Clean the throttle body with a safe cleaner and a soft cloth; if it's damaged or heavily coked, consider replacement.
5. Check the MAF/MAP sensors and their connectors: fit, corrosion, and wiring damage.
6. After the intake repair, run the throttle body adaptation procedure with a bidirectional scanner if needed before concluding the repair didn't work.
7. Clear the code and take a test drive to confirm the fault is fixed.