P016B
Closed Loop Air/Fuel Ratio Control At Limit - System Too Rich
Closed-loop fuel trim hit its lean correction limit because mixture is structurally too rich. Likely fuel pressure too high, leaking injector, or O2 sensor reporting too lean.
Closed-loop fuel trim hit its lean correction limit because mixture is structurally too rich. Likely fuel pressure too high, leaking injector, or O2 sensor reporting too lean.
Common causes
- high
Injector leaking
One of the most commonly reported causes for this code — check this first.
Typical part cost: $170-2200
See all causes + fix costs
Create a free Wrenchify account to unlock the rest for P016B.
Unlock causesFree forever · No credit card
First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
Get the full step-by-step diagnosis
Create a free Wrenchify account to unlock the rest for P016B.
Unlock diagnosisFree forever · No credit card
Related codes
See related trouble codes
Create a free Wrenchify account to unlock the rest for P016B.
Unlock related codesFree forever · No credit card
Frequently asked questions
What does P016B mean?
P016B means "Closed Loop Air/Fuel Ratio Control At Limit - System Too Rich". It is a generic OBD-II code that points to a fault in the fuel & air metering.
What are the most common causes of P016B?
injector leaking — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly. Use the Wrenchify app for a full diagnosis specific to your vehicle.
Get the full P016B diagnosis for your vehicle
Year, make, model + step-by-step repair help — free plan included.