Network, generic

U0324 Software Incompatibility With HVAC Control Module

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

The HVAC control module reads cabin and outside temperatures and drives blend doors, blower, defrosting and the request for the A/C compressor. U0324 means another controller has found its software or calibration unfit for the vehicle. No manufacturer documents U0324 publicly; GM bulletins show how tightly the HVAC calibration is tied to other parts. On 2018 Chevrolet Equinox and GMC Terrain the climate system stayed off during remote start below 6 °C because of a calibration issue in the HVAC module, cured by reprogramming (17-NA-388). On 2013–2016 Cadillac ATS automatic rear window and mirror defogging failed after a recall; Techline supplies HVAC software that matches a new radio antenna coil (16-NA-008). U0164 is lost contact, U0424 invalid data, U032A concerns the compressor module. Climate functions are limited, no MIL.

Likely causes

HVAC module calibration outdated or not matching the vehicle options
Connected part replaced, such as antenna, display or compressor, without matching HVAC software
HVAC module replaced or taken from another car without setup

Symptoms

  • Heating, cooling or defrosting works only in part
  • Climate settings reset or remote start climate stays off
  • A/C compressor not requested

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€60–600
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

hvac modulecontrol module software

Related codes

U0164U0424U032AU0325

References: static.nhtsa.gov, static.nhtsa.gov, en.wikipedia.org.