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Diagnostic knowledge / P016B — Closed loop mixture control, limit reached - system too rich
P016B

Closed loop mixture control, limit reached - system too rich

P016B is described as “Closed loop mixture control, limit reached - system too rich” in the Generic OBD2 reference.

Some scan tools (for example GM and Ford dealer tools) display this code with a failure-type suffix, such as P016B-00 or P016B:00; the base code P016B is the same.

Generic OBD2

Generic OBD2: P016B

en

Closed loop mixture control, limit reached - system too rich

Reference namespace
obd2
Source revision
legacy-2.2.20

Generic OBD2 definition; confirm the protocol and vehicle-specific service information.

What should I check before using this definition?

Keep the full code, module, status and freeze-frame data. Confirm the vehicle’s make, model, year and current manufacturer service information before choosing a repair. This entry does not identify a failed part by itself.

Organize a scan report or recording
Source and applicability

OBD Lens production library legacy-owner-2026-11-02-v84-evidence. This is a scoped technical reference, not a scan of your car. A catalog relationship does not certify that every ECU, year or engine returns the same signal or code definition.

Read the reference method

What does P016B mean?

Closed loop mixture control, limit reached - system too rich. 1 reference families define this identifier: Generic OBD2.

Is P016B a generic or manufacturer-specific code?

This code has a generic OBD-II prefix. Confirm the reference scope shown above.

Can P016B tell me which part has failed?

This entry does not identify a failed part by itself. Confirm the vehicle’s make, model, year and current manufacturer service information before choosing a repair.

OBD Lens reference library · catalog legacy-owner-2026-11-02-v84-evidence. Sources and scope