OBD Guide
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B2798

Communication Malfunction No. 2 Immobilizer System

B2798 is an OBD-II diagnostic trouble code meaning: Communication Malfunction No. 2 Immobilizer System. Common causes: open or short circuit in the immobilizer wiring harness, immobilizer module 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
  • Check Engine Light Is On
  • Car stalls after starting
  • Immobilizer does not recognize the key

Causes

  • Open or short circuit in the immobilizer wiring harness
  • Immobilizer module malfunction
  • Damage to the immobilizer antenna
  • ECU malfunction
  • Problems with the key (chip damage, low battery)

How to Fix

  1. Check the condition of the immobilizer wiring harness for damage.
  2. Check connections and connectors of the immobilizer module
  3. Diagnose the immobilizer module and antenna
  4. Check the condition of the key and its chip
  5. If necessary, reprogram the keys or replace the immobilizer module

Related codes

B2799P0513P0633

FAQ

What does the B2798 code mean?

B2798 is an OBD-II diagnostic trouble code that indicates: Communication Malfunction No. 2 Immobilizer System

What causes a B2798 error code?

The most common causes of B2798 include: Open or short circuit in the immobilizer wiring harness; Immobilizer module malfunction; Damage to the immobilizer antenna; ECU malfunction.

How do I fix a B2798 diagnostic trouble code?

To fix B2798: Check the condition of the immobilizer wiring harness for damage.. Check connections and connectors of the immobilizer module. Diagnose the immobilizer module and antenna. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B2798?

Yes, but get it checked soon

How much does it cost to fix B2798?

The estimated repair cost for B2798 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat