What Does U0425 Mean?
The control module is receiving corrupted or implausible data from the auxiliary heater control module over the vehicle communication network. This indicates a communication problem rather than a heater malfunction itself.
Common Causes
35%
Faulty auxiliary heater control module sending corrupted data
30%
Damaged or corroded wiring/connectors in the CAN bus circuit to auxiliary heater module
20%
Low system voltage or poor ground at auxiliary heater module
10%
Software version mismatch or corrupted firmware in auxiliary heater module
5%
Faulty receiving control module misinterpreting valid data
Diagnostic Steps
1
Step 1: Check for other U-codes that may indicate widespread network issues versus isolated module problem
2
Step 2: Verify battery voltage and ground connections at auxiliary heater control module (minimum 11V required)
3
Step 3: Inspect wiring harness and connectors between auxiliary heater module and CAN bus for damage, corrosion, or loose connections
4
Step 4: Use advanced scan tool to monitor live data from auxiliary heater module and verify data plausibility
5
Step 5: Check for available software updates for auxiliary heater control module and reflash if needed
Estimated Repair Cost
$100 - $650
Parts + labor, varies by vehicle and location
The control module is receiving corrupted or implausible data from the auxiliary heater control module over the vehicle communication network. This indicates a communication problem rather than a heater malfunction itself.
The most common cause of U0425 (Invalid Data Received From Auxiliary Heater Control Module) is: Faulty auxiliary heater control module sending corrupted data
Typical repair costs for U0425 range from $100 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
No direct safety concern. Auxiliary heater may not function properly, affecting cabin comfort in cold weather.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U0425 to identify the root cause.
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Quick Info
Category
Network
System
Network Communication / Auxiliary Heating
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
