Invalid Data Received From HVAC Control Module
What does U0404 mean?
The U0404 code means the vehicle's onboard diagnostic system has detected: Invalid Data Received From HVAC Control Module. This is a low severity code.
Common Symptoms
- Climate control not maintaining set temperature
- Air blowing from wrong vents
- Temperature display showing incorrect readings
- Automatic climate mode not working correctly
- Blower speed changing unexpectedly
Probable Causes (Ranked by Likelihood)
- HVAC control module sending incorrect sensor data Very High
- Failed interior temperature sensor High
- Blend door actuator sending wrong position data Moderate
- Wiring issue between HVAC module and BCM Low
Step-by-Step Diagnostic Procedure
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Check interior temperature sensor readings with a scan tool
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Verify blend door actuator positions match commanded positions
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Inspect wiring to the HVAC module and temperature sensors
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Check the ambient temperature sensor for accurate readings
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Monitor HVAC live data for erratic or impossible values
Frequently Asked Questions
Can I drive with code U0404?
Yes, safe to drive. The climate control may not maintain the correct temperature but no driving systems are affected.
What causes U0404?
Usually a failed temperature sensor or blend door actuator sending incorrect data to the HVAC module. These sensors can degrade over time.
Is U0404 expensive to fix?
Typically $100 to $500. Temperature sensor replacement is inexpensive. Blend door actuator replacement can be more costly due to dashboard disassembly.