OBD Guide
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B2921

Auxiliary Blend Door Feedback Circuit Open/Shorted

B2921 is an OBD-II diagnostic trouble code meaning: Auxiliary Blend Door Feedback Circuit Open/Shorted. Common causes: open or shorted wiring harness, damper position sensor malfunction. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Incorrect operation of the climate control system
  • Uneven air distribution in the cabin
  • Lack of response to changing temperature settings

Causes

  • Open or shorted wiring harness
  • Damper position sensor malfunction
  • Mechanical jamming of the damper
  • Problems with the climate control unit

How to Fix

  1. Check the integrity of the wiring harness
  2. Check the operation of the damper position sensor
  3. Inspect the damper mechanism for jamming
  4. If necessary, replace faulty components

Related codes

B2920B2922

FAQ

What does the B2921 code mean?

B2921 is an OBD-II diagnostic trouble code that indicates: Auxiliary Blend Door Feedback Circuit Open/Shorted

What causes a B2921 error code?

The most common causes of B2921 include: Open or shorted wiring harness; Damper position sensor malfunction; Mechanical jamming of the damper; Problems with the climate control unit.

How do I fix a B2921 diagnostic trouble code?

To fix B2921: Check the integrity of the wiring harness. Check the operation of the damper position sensor. Inspect the damper mechanism for jamming. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B2921?

Yes, but get it checked soon

How much does it cost to fix B2921?

The estimated repair cost for B2921 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat