P016C
Closed Loop Air/Fuel Ratio Control At Limit System Too Lean
Generic OBD-II
Common symptoms
What you'll notice
- Check for any vacuum leaks or air intake leaks
- Inspect and clean the mass airflow sensor
- Test and possibly replace the oxygen sensor
- Check and clean the fuel injectors
- Inspect and clean the throttle body
Common causes
Most likely first
- Clogged or dirty fuel injectors
- Faulty oxygen sensor
- Vacuum leaks in the intake manifold or hoses
- Defective mass airflow sensor (MAF)
- Faulty fuel pressure regulator
How to diagnose & fix
Work through it in order
- Engine misfires or runs rough
- Decreased engine power or performance
- Surging or hesitation during acceleration
- Poor fuel efficiency or increased fuel consumption
- Illumination of the check engine light (MIL)
Read & clear P016C yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.