What does B0239 mean on a Chevy?

B0239. Defrost door circuit range fault. The defrost door moves outside its expected range and the body warning light comes on. Applies to Chevrolet, GMC, Buick, Cadillac, Pontiac, Oldsmobile and Saturn models that use this code.

What causes B0239 on a Chevy?

Defrost door binding and stalling its actuator Defrost door actuator position sensor out of calibration Open or short in the defrost door actuator circuit Corroded or loose defrost door actuator connector Faulty output inside the HVAC control module

How do I fix B0239 on a Chevy?

Confirm the code with a scan tool and watch the defrost door command and position Command the defrost door through full travel and note where it stalls Inspect and reseat the defrost door actuator connector Move the defrost door by hand to check for binding Replace the defrost door actuator only after the circuit tests pass, then clear the code and retest

Code

B0239

Defrost door circuit range fault

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

B0239. Defrost door circuit range fault. The defrost door moves outside its expected range 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

Defrost door binding and stalling its actuator
Defrost door actuator position sensor out of calibration
Open or short in the defrost door actuator circuit
Corroded or loose defrost door actuator connector
Faulty output inside the HVAC control module

Standard procedure

Confirm the code with a scan tool and watch the defrost door command and position
Command the defrost door through full travel and note where it stalls
Inspect and reseat the defrost door actuator connector
Move the defrost door by hand to check for binding
Replace the defrost 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 B0239 definition | OBDII.pro
live manufacturer definition (obdii.pro)
Supports: GM manufacturer meaning for B0239
Fetched directly. The GM entry is the brand-family meaning used here. This site is independent of engine-codes and autocodes.
B0239 CHEVROLET Air flow control #1 (defrost) circuit range/performance | Engine-Codes.com
archived reference page (engine-codes.com via Wayback Machine)
Supports: Chevrolet meaning and possible causes for B0239
Fetched directly. Model and year fitment remain curator claims.
B0239 CHEVROLET Air Flow Control 1 Circuit Performance | AutoCodes.com
archived reference page (autocodes.com via Wayback Machine)
Supports: corroboration of Chevrolet meaning and causes for B0239
Same Chevrolet text as the engine-codes page (both sites share one publisher).

Last updated 2026-10-10.

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