OBD Guide
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B1235

Problem In The Driver Side Air Mix Control Linkage, Door, Or Motor Circuit

B1235 is an OBD-II diagnostic trouble code meaning: Problem In The Driver Side Air Mix Control Linkage, Door, Or Motor Circuit. Common causes: air mixture damper jammed, damper motor malfunction. Estimated repair cost: $33–167.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$33–167 (est.)

Symptoms

  • Inability to regulate air temperature on the driver's side
  • Constant flow of only hot or only cold air
  • Rattling sounds from under the panel when the climate control is operating

Causes

  • Air mixture damper jammed
  • Damper motor malfunction
  • Open or short circuit in control circuit
  • Problems with the HVAC control unit

How to Fix

  1. Check and clean the damper mechanism from dirt and debris
  2. Test the damper motor
  3. Check the integrity of the wiring harness and connectors
  4. Measure resistance and voltage in the control circuit
  5. If necessary, replace faulty components

Related codes

B1236B1234B1237B1238

FAQ

What does the B1235 code mean?

B1235 is an OBD-II diagnostic trouble code that indicates: Problem In The Driver Side Air Mix Control Linkage, Door, Or Motor Circuit

What causes a B1235 error code?

The most common causes of B1235 include: Air mixture damper jammed; Damper motor malfunction; Open or short circuit in control circuit; Problems with the HVAC control unit.

How do I fix a B1235 diagnostic trouble code?

To fix B1235: Check and clean the damper mechanism from dirt and debris. Test the damper motor. Check the integrity of the wiring harness and connectors. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1235?

Yes, but get it checked soon

How much does it cost to fix B1235?

The estimated repair cost for B1235 is $33–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat