What does B0238 mean on a Chevy?

B0238. Defrost door circuit malfunction. The HVAC module cannot command the defrost door and the body warning light comes on. Applies to Chevrolet, GMC, Buick, Cadillac, Pontiac, Oldsmobile and Saturn models that use this code.

What causes B0238 on a Chevy?

Binding or stripped defrost door actuator gears Open or short in the defrost door actuator circuit Corroded or loose defrost door actuator connector Failed defrost door position sensor inside the actuator Faulty output inside the HVAC control module

How do I fix B0238 on a Chevy?

Confirm the code with a scan tool and command the defrost door through full travel Inspect and reseat the defrost door actuator connector Test the defrost door circuit for opens, shorts and voltage drop Move the defrost door by hand with the actuator removed to check for binding Replace the defrost door actuator only after the circuit tests pass, then clear the code and retest

Code

B0238

Defrost door circuit malfunction

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

B0238. Defrost door circuit malfunction. The HVAC module cannot command the defrost door 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

Binding or stripped defrost door actuator gears
Open or short in the defrost door actuator circuit
Corroded or loose defrost door actuator connector
Failed defrost door position sensor inside the actuator
Faulty output inside the HVAC control module

Standard procedure

Confirm the code with a scan tool and command the defrost door through full travel
Inspect and reseat the defrost door actuator connector
Test the defrost door circuit for opens, shorts and voltage drop
Move the defrost door by hand with the actuator removed 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: qualified. Read the source limits below.

Code B0238 definition | OBDII.pro
live manufacturer definition (obdii.pro)
Supports: GM manufacturer meaning for B0238
Fetched directly. The GM entry is the brand-family meaning used here. This site is independent of engine-codes and autocodes.
B0238 CHEVROLET Mode Door Circuit Range | Engine-Codes.com
archived reference page (engine-codes.com via Wayback Machine)
Supports: Chevrolet meaning and possible causes for B0238
Fetched directly. Model and year fitment remain curator claims.
B0238 CHEVROLET Air Flow Control 1 Circuit | AutoCodes.com
archived reference page (autocodes.com via Wayback Machine)
Supports: corroboration of Chevrolet meaning and causes for B0238
Same Chevrolet text as the engine-codes page (both sites share one publisher).

Review note: obdii.pro GM names air flow control 1 for the defrost door as a malfunction; the engine-codes archive names the mode door circuit range while autocodes names air flow control 1 circuit. The fault type conflicts, so the record uses the GM wording and flags it

Last updated 2026-10-10.

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