B0408 on Chevrolet
Temperature Control (Air Mix) Circuit Malfunction
B0408 on Chevrolet vehicles indicates temperature control (air mix) circuit malfunction. Au7o has documented this code across 1 Chevrolet model — most commonly on Malibu. B0408 is a body (B) code relating to the climate control system's temperature/air-mix control circuit. It generally means the HVAC module detected a fault in the circuit that controls the air-mix (blend) door, which regulates how much air is blended for the desired cabin temperature. Exact wording is somewhat manufacturer-specific, but it typically results in inability to control temperature on one or both sides. This is a comfort-system fault and not a safety or drivability hazard. Typical repair costs on Chevrolet range from $200 to $1,500, depending on the specific model and root cause.
Common Causes of B0408
- •Failed air-mix (blend door) actuator/servo motor
- •Broken or jammed blend door
- •Wiring or connector fault in the actuator circuit
- •Loss of power or ground to the actuator
- •Faulty HVAC control module
- •Calibration/positioning fault after battery disconnect
B0408 on Chevrolet by Model
Chevrolet Malibu(1 issue)
- A/C Compressor Clutch Failure2008-2020
The A/C compressor clutch on the Malibu fails due to a burned-out clutch coil, worn clutch plate, or bearing failure in the compressor pulley. When the clutch fails, the A/C blows warm air because the compressor cannot engage. A squealing or grinding noise from the serpentine belt area is common before total failure. The compressor clutch can also seize, which will shred the serpentine belt and cause a loss of all belt-driven accessories (alternator, power steering, water pump).
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View B0408 across all makes →Frequently Asked Questions
What does B0408 mean on Chevrolet?▼
B0408 stands for "Temperature Control (Air Mix) Circuit Malfunction." B0408 is a body (B) code relating to the climate control system's temperature/air-mix control circuit. It generally means the HVAC module detected a fault in the circuit that controls the air-mix (blend) door, which regulates how much air is blended for the desired cabin temperature. Exact wording is somewhat manufacturer-specific, but it typically results in inability to control temperature on one or both sides. This is a comfort-system fault and not a safety or drivability hazard. On Chevrolet specifically, this code is documented across 1 model.
What causes B0408 on Chevrolet vehicles?▼
Common causes on Chevrolet: Failed air-mix (blend door) actuator/servo motor, Broken or jammed blend door, Wiring or connector fault in the actuator circuit, Loss of power or ground to the actuator, Faulty HVAC control module. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix B0408 on a Chevrolet?▼
Repair costs on Chevrolet range from $200 to $1,500, depending on the specific model and root cause.
Which Chevrolet models have B0408 documented?▼
Au7o has documented B0408 on 1 Chevrolet model: Malibu.