WRENCHIFY
Quick decodeBack to home
All codes/P016B

P016B

Closed Loop Air/Fuel Ratio Control At Limit - System Too Rich

High severity

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

  • Injector leaking

    One of the most commonly reported causes for this code — check this first.

    high

    Typical part cost: $170-2200

  • See all causes + fix costs

    Create a free Wrenchify account to unlock the rest for P016B.

    Unlock causes

    Free forever · No credit card

First things to check

  1. 1Confirm the code with a scan tool and check for additional related codes.
  2. 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 diagnosis

Free forever · No credit card

Tools you may need

Already have a compatible scanner? Use it. If not, a Bluetooth OBD2 adapter can help you confirm engine codes and check supported live sensor data before replacing parts.

Illustration of a Bluetooth OBD2 adapter, not a product photo

Basic checks

Veepeak OBDCheck BLE

A Bluetooth LE adapter for reading standard engine codes and supported live data.

View on Amazon
Illustration of a Bluetooth OBD2 adapter, not a product photo

Regular diagnostics

vgate iCar Pro BLE 4.0

A Bluetooth LE adapter with an automatic sleep feature for routine code and sensor checks.

View on Amazon
Illustration of a Bluetooth OBD2 adapter, not a product photo

Another option

OBDLink CX

A Bluetooth LE adapter to consider when comparing supported vehicles and diagnostic apps.

View on Amazon

Illustrations shown, not product photos. Check vehicle, phone and app compatibility before buying. These adapters do not guarantee access to ABS, airbags or manufacturer-specific systems. Clearing a code does not repair the fault and can reset emissions readiness monitors.

As an Amazon Associate, Wrenchify earns from qualifying purchases. This supports the app at no extra cost to you.

Related codes

See related trouble codes

Create a free Wrenchify account to unlock the rest for P016B.

Unlock related codes

Free 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.

Diagnose P016B