OBD Guide
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B1A35

Unidentified Key Communication Error

B1A35 is an OBD-II diagnostic trouble code meaning: Unidentified Key Communication Error. Common causes: dead battery in the key, immobilizer antenna malfunction. Estimated repair cost: $56–167.

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

Symptoms

  • Engine won't start
  • The immobilizer indicator is flashing
  • No response when pressing the start button

Causes

  • Dead battery in the key
  • Immobilizer antenna malfunction
  • Wiring harness damage
  • Control unit software error

How to Fix

  1. Check the battery in the key
  2. Diagnose the immobilizer antenna
  3. Check the integrity of the wiring harness
  4. Update control unit software

Related codes

B1A36B1A37

FAQ

What does the B1A35 code mean?

B1A35 is an OBD-II diagnostic trouble code that indicates: Unidentified Key Communication Error

What causes a B1A35 error code?

The most common causes of B1A35 include: Dead battery in the key; Immobilizer antenna malfunction; Wiring harness damage; Control unit software error.

How do I fix a B1A35 diagnostic trouble code?

To fix B1A35: Check the battery in the key. Diagnose the immobilizer antenna. Check the integrity of the wiring harness. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1A35?

Yes, but get it checked soon

How much does it cost to fix B1A35?

The estimated repair cost for B1A35 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat