OBD Guide
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B279A

Theft Deterrent System Communication Line High Fixation

B279A is an OBD-II diagnostic trouble code meaning: Theft Deterrent System Communication Line High Fixation. Common causes: short circuit to +12v in the communication circuit, wiring harness damage. Estimated repair cost: $56–278.

Severity
🔴 High
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$56–278 (est.)

Symptoms

  • Check engine light is on
  • Problems starting the engine
  • The car does not respond to the alarm key fob
  • Immobilizer emergency mode activated

Causes

  • Short circuit to +12V in the communication circuit
  • Wiring harness damage
  • Oxidation of contacts
  • Immobilizer module malfunction
  • Problems with the engine control unit (ECU)

How to Fix

  1. Check the integrity of the anti-theft system wiring harness
  2. Diagnose voltage in the communication circuit
  3. Check connections and connector contacts
  4. Scan for other related trouble codes
  5. If necessary, replace or reprogram the immobilizer module

Related codes

B279BB2799P0513P0633

FAQ

What does the B279A code mean?

B279A is an OBD-II diagnostic trouble code that indicates: Theft Deterrent System Communication Line High Fixation

What causes a B279A error code?

The most common causes of B279A include: Short circuit to +12V in the communication circuit; Wiring harness damage; Oxidation of contacts; Immobilizer module malfunction.

How do I fix a B279A diagnostic trouble code?

To fix B279A: Check the integrity of the anti-theft system wiring harness. Diagnose voltage in the communication circuit. Check connections and connector contacts. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B279A?

Yes, but get it checked soon

How much does it cost to fix B279A?

The estimated repair cost for B279A is $56–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat