OBD Guide
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P1678

Immobilizer Powertrain Identification Failed

P1678 is an OBD-II diagnostic trouble code meaning: Immobilizer Powertrain Identification Failed. Common causes: faulty ignition key (chip), damage to the immobilizer antenna. Estimated repair cost: $33–167.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$33–167 (est.)

Symptoms

  • Engine won't start
  • The engine stalls immediately after starting
  • The immobilizer indicator is on
  • Check Engine light comes on
  • No response when turning the ignition key

Causes

  • Faulty ignition key (chip)
  • Damage to the immobilizer antenna
  • Problems with the immobilizer wiring harness
  • ECU software failure
  • Immobilizer unit malfunction

How to Fix

  1. Check the condition of the ignition key
  2. Diagnose the immobilizer antenna
  3. Check the integrity of the wiring harness
  4. Reprogram the immobilizer system
  5. Repair only from an authorized dealer

Related codes

P1676P1677B3100

Error P1678 by Vehicle Brand

AcuraHondaInfinitiVolkswagen

FAQ

What does the P1678 code mean?

P1678 is an OBD-II diagnostic trouble code that indicates: Immobilizer Powertrain Identification Failed

What causes a P1678 error code?

The most common causes of P1678 include: Faulty ignition key (chip); Damage to the immobilizer antenna; Problems with the immobilizer wiring harness; ECU software failure.

How do I fix a P1678 diagnostic trouble code?

To fix P1678: Check the condition of the ignition 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 P1678?

Do not drive — repair immediately

How much does it cost to fix P1678?

The estimated repair cost for P1678 is $33–167. Actual cost depends on your vehicle, location, and labor rates.

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