U0424

Invalid Data Received From HVAC Control Module

Q: Is it safe to drive with U0424?

Yes. It only affects the climate system. The main inconvenience is heating, A/C, or defog not working properly — clear defog before cold or wet weather driving.

Q: Can I just clear U0424?

It returns while the module reports bad data. Check power and wiring, then the HVAC module, rather than just clearing.

Communication network Generic OBD-II Low

What it means

U0424 is a network communication code: a module is receiving data from the HVAC (heating, ventilation, and air-conditioning) control module that is corrupt, missing, or out of range. Communication is working, but the values are wrong. It affects the climate system only — engine and safety systems are unaffected — so the main symptom is climate control not working the way it should.

Low

Can I keep driving? Safe to drive — this affects climate control, not engine or safety systems; heating, A/C, or defog may not work correctly.

Real-world scan data

Seen in

193

scans in the past year

Found in

<0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of U0424 scans

U0100in 48.2% of scans

B1322in 37.8% of scans

B1A28in 37.3% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Climate control behaving erratically or not responding
Wrong temperature, fan speed, or airflow-mode output
HVAC display or controls blank or frozen
Automatic climate features not adjusting as expected

Common causes

Most likely first

Internal fault in the HVAC control module sending corrupt dataLikely
Wiring or connector problems on the bus to the HVAC moduleCommon
Low system voltage or a poor ground at the moduleCommon
Failed HVAC sensor (in-car temperature, blend-door, etc.) feeding bad valuesLess often

How to diagnose & fix

Work through it in order

Scan all modules and note freeze-frame data; clear any lost-communication codes first.
Check battery voltage and the HVAC module's ground.
Inspect the module connector and bus wiring for corrosion or loose pins.
Test HVAC sensors and actuators for range faults.
If wiring, power, and sensors are good, suspect the HVAC control module and confirm with manufacturer tests.

FAQ

Quick answers

Is it safe to drive with U0424?+

Yes. It only affects the climate system. The main inconvenience is heating, A/C, or defog not working properly — clear defog before cold or wet weather driving.

Can I just clear U0424?+

It returns while the module reports bad data. Check power and wiring, then the HVAC module, rather than just clearing.

Read & clear U0424 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX