U0424 code meaning
Invalid Data Received From HVAC Control Module
Network system Generic code U04xx codes Check engine light
What U0424 means
The HVAC control module reports climate requests and, on newer layouts, also the voltages of switches on the climate faceplate that it measures itself. U0424 says a receiver rejects these frames. GM documents the logic in the BCM of its 2025 vehicles: alive rolling counts, protection values, checksums or CRCs of the HVAC messages are checked every 10 ms, and 8 failures in 10 samples set a Type B fault once the BCM has been up for 5 s, the partial network has run for 3 s, power mode is Run and the battery has more than 11 V. As long as U0164 or U0424 is present the BCM suspends its faceplate switch tests (B2A01 and others), since their values come over CAN. GM's Saab 9-5 list (2011) contains U0424, and Ford marks it with the MIL in its 2014 code interpretation. U0164 is lost contact, U0324 software.
U0424 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0424
- Climate controls or buttons react incorrectly or not at all
- A/C or defrost not available
- Check engine light on some makes
Common causes of U0424
- PossibleHVAC control module or faceplate electronics faulty
- PossibleLow battery voltage or a reset of the HVAC module during start-up
- Less likelyHVAC or BCM software level that needs an update
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hvac control moduleCAN bus wiring
What each part of U0424 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 24 | The exact fault in that area. |
What to do next
- Note U0424 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0424
What does U0424 mean?
U0424 means "Invalid Data Received From HVAC Control Module". The HVAC control module reports climate requests and, on newer layouts, also the voltages of switches on the climate faceplate that it measures itself. It is a generic code, so it means the same on every make.
Is it safe to drive with U0424?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U0424 fail an emissions test?
Yes, it can. U0424 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U0424 to fix?
Difficulty: workshop only. A typical repair takes 0.3 to 2 hours of work. This is a job for a workshop.
Will U0424 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.