OBD Guide
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C2171

Transmitter ID not Registered

C2171 is an OBD-II diagnostic trouble code meaning: Transmitter ID not Registered. Common causes: faulty transponder in the key, damage to the immobilizer antenna. Estimated repair cost: $33–111.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$33–111 (est.)

Symptoms

  • The car won't start
  • The immobilizer indicator is flashing
  • The engine stalls after a few seconds

Causes

  • Faulty transponder in the key
  • Damage to the immobilizer antenna
  • Control unit software failure
  • Dead key battery (if equipped)
  • Mechanical damage to the ignition switch

How to Fix

  1. Diagnostics of the key and immobilizer system
  2. Checking the condition of the immobilizer antenna
  3. Re-registering a key using diagnostic equipment
  4. Repair or replace damaged components
  5. Reflashing the control unit if necessary

Related codes

B3055P0513B3101

FAQ

What does the C2171 code mean?

C2171 is an OBD-II diagnostic trouble code that indicates: Transmitter ID not Registered

What causes a C2171 error code?

The most common causes of C2171 include: Faulty transponder in the key; Damage to the immobilizer antenna; Control unit software failure; Dead key battery (if equipped).

How do I fix a C2171 diagnostic trouble code?

To fix C2171: Diagnostics of the key and immobilizer system. Checking the condition of the immobilizer antenna. Re-registering a key using diagnostic equipment. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C2171?

Yes, but get it checked soon

How much does it cost to fix C2171?

The estimated repair cost for C2171 is $33–111. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat