What does B0266 mean on a Chevy?

B0266. A/C air flow control door circuit high. The command signal to that door reads high and the body warning light comes on. Applies to Chevrolet, GMC, Buick, Cadillac, Pontiac, Oldsmobile and Saturn models that use this code.

What causes B0266 on a Chevy?

A/C air flow control door command signal shorted to voltage Failed A/C air flow control door actuator holding the command signal high Open in the A/C air flow control door command return Corroded or loose A/C air flow control door actuator connector Faulty output inside the HVAC control module

How do I fix B0266 on a Chevy?

Confirm the code with a scan tool and command the A/C air flow control door Measure the A/C air flow control door command voltage at the actuator Inspect and reseat the A/C air flow control door actuator connector Test the A/C air flow control door command circuit for a short to voltage Replace the A/C air flow control door actuator only after the circuit tests pass, then clear the code and retest

Code

B0266

A/C air flow control door circuit high

Category: Body
Severity: Body Warning Light
Applies to: Chevrolet, GMC, Buick, Cadillac, Pontiac, Oldsmobile and Saturn models that use this code
Related: No single generic twin. See OBD Codes List

What it means

B0266. A/C air flow control door circuit high. The command signal to that door reads high and the body warning light comes on. This Chevy-enhanced code applies to Chevrolet, GMC, Buick, Cadillac, Pontiac, Oldsmobile and Saturn models that use this code.

Findings, check these first

A/C air flow control door command signal shorted to voltage
Failed A/C air flow control door actuator holding the command signal high
Open in the A/C air flow control door command return
Corroded or loose A/C air flow control door actuator connector
Faulty output inside the HVAC control module

Standard procedure

Confirm the code with a scan tool and command the A/C air flow control door
Measure the A/C air flow control door command voltage at the actuator
Inspect and reseat the A/C air flow control door actuator connector
Test the A/C air flow control door command circuit for a short to voltage
Replace the A/C air flow control door actuator only after the circuit tests pass, then clear the code and retest

Look up another code

Press / to jump to the box. Chevy-enhanced powertrain, body, chassis and network codes.

Sources and review

Review: checked against the recorded source material.

Code B0266 definition | OBDII.pro
live manufacturer definition (obdii.pro)
Supports: GM manufacturer meaning for B0266
Fetched directly. The GM entry is the brand-family meaning used here. This site is independent of engine-codes and autocodes.
B0266 CHEVROLET Air Flow Control 6 Circuit High | Engine-Codes.com
archived reference page (engine-codes.com via Wayback Machine)
Supports: Chevrolet meaning and possible causes for B0266
Fetched directly. Model and year fitment remain curator claims.
B0266 CHEVROLET Air Flow Control 6 Circuit High | AutoCodes.com
archived reference page (autocodes.com via Wayback Machine)
Supports: corroboration of Chevrolet meaning and causes for B0266
Same Chevrolet text as the engine-codes page (both sites share one publisher).

Last updated 2026-10-10.

Report a correction for B0266. Include your vehicle, the issue and a source if you have one.