OBD Guide

U0664

Lost Communication With Rear HVAC Air Cutoff Actuator

U0664 is an OBD-II diagnostic trouble code meaning: Lost Communication With Rear HVAC Air Cutoff Actuator. Common causes: open or short circuit in control circuit, damper actuator malfunction. Estimated repair cost: $13–94.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$13–94 (est.)

Symptoms

  • It is impossible to regulate the air supply to the rear seats
  • Uneven airflow distribution
  • Rear deflectors do not respond to settings
  • Hot/cold air is not supplied correctly

Causes

  • Open or short circuit in control circuit
  • Damper actuator malfunction
  • Rear HVAC Unit Wiring Harness Problems
  • Climate control circuit fuse blown
  • Oxidation of connector contacts

How to Fix

  1. Check climate system fuses
  2. Diagnose the damper mechanism with a multimeter
  3. Check the integrity of the wires to the rear HVAC unit
  4. Clean the connector contacts
  5. If necessary, replace the actuator

Related codes

Error U0664 by Vehicle Brand

FAQ

What does the U0664 code mean?

U0664 is an OBD-II diagnostic trouble code that indicates: Lost Communication With Rear HVAC Air Cutoff Actuator

What causes a U0664 error code?

The most common causes of U0664 include: Open or short circuit in control circuit; Damper actuator malfunction; Rear HVAC Unit Wiring Harness Problems; Climate control circuit fuse blown.

How do I fix a U0664 diagnostic trouble code?

To fix U0664: Check climate system fuses. Diagnose the damper mechanism with a multimeter. Check the integrity of the wires to the rear HVAC unit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U0664?

Yes, but get it checked soon

How much does it cost to fix U0664?

The estimated repair cost for U0664 is $13–94. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat