U0166
Lost Communication With Auxiliary Heater Control Module
U0166 is an OBD-II diagnostic trouble code meaning: Lost Communication With Auxiliary Heater Control Module. Common causes: broken or damaged can bus wires, heater module power supply problems. Estimated repair cost: $56–278.
Symptoms
- Auxiliary heater does not work
- Error indication on the instrument panel
- Reduced comfort in the cabin in winter
- Other CAN bus errors are possible
Causes
- Broken or damaged CAN bus wires
- Heater module power supply problems
- Heater control module malfunction
- Corrosion of contacts or connectors
- Problems with the main ECU
How to Fix
- Check the integrity of the wiring harness to the heater module
- Check the power supply and ground of the module
- Inspect connectors for corrosion
- Scan the CAN bus for other errors
- If necessary, replace the heater control module
Related codes
Error U0166 by Vehicle Brand
FAQ
What does the U0166 code mean?
U0166 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Auxiliary Heater Control Module
What causes a U0166 error code?
The most common causes of U0166 include: Broken or damaged CAN bus wires; Heater module power supply problems; Heater control module malfunction; Corrosion of contacts or connectors.
How do I fix a U0166 diagnostic trouble code?
To fix U0166: Check the integrity of the wiring harness to the heater module. Check the power supply and ground of the module. Inspect connectors for corrosion. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U0166?
Yes, but get it checked soon
How much does it cost to fix U0166?
The estimated repair cost for U0166 is $56–278. Actual cost depends on your vehicle, location, and labor rates.
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