U0427
NetworkModule Communicationlow severityInvalid Data Received From Fuel Fired Heater Control Module
What U0427 Means
The vehicle's network is receiving corrupt or implausible data from the fuel fired (auxiliary) heater control module. This usually points to a communication fault or a problem inside the heater module itself.
Symptoms
- Auxiliary heater not working
- Warning light on dash
- Poor cabin or engine heating in cold weather
Common Causes
- Faulty fuel fired heater control module
- Wiring or connector corrosion at module
- CAN bus communication fault
- Low battery voltage or bad ground
Diagnostic Steps
- Scan all modules for related U-codes
- Check heater module wiring and connectors
- Verify power and ground at module
- Test CAN bus signals for the module
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ANCEL AD410 →
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Serious DIY~$100
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Autel MaxiCOM MK808S →
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Autel MaxiSys MS906 Pro →
Full-system pro platform — topology mapping, ECU coding, the works.
✓ Autel official store
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