OBD Guide
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U1A04

Telematics Control Unit VIN Unfinished

U1A04 is an OBD-II diagnostic trouble code meaning: Telematics Control Unit VIN Unfinished. Common causes: replacing the telematics control unit, vin programming failure.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon

Symptoms

  • Error message on display
  • Telematic services do not work
  • Emergency calls may not function
  • Lack of remote access to the car

Causes

  • Replacing the telematics control unit
  • VIN programming failure
  • Problems with communication between blocks
  • TCU software error
  • TCU memory corruption

How to Fix

  1. Check service history for TCU replacement
  2. Read current VIN from TCU using diagnostic equipment
  3. Compare VIN from TCU with vehicle VIN
  4. If necessary, reprogram VIN in TCU
  5. Update TCU software
  6. Repair only from an authorized dealer

Related codes

U1A00U1A03U0155

FAQ

What does the U1A04 code mean?

U1A04 is an OBD-II diagnostic trouble code that indicates: Telematics Control Unit VIN Unfinished

What causes a U1A04 error code?

The most common causes of U1A04 include: Replacing the telematics control unit; VIN programming failure; Problems with communication between blocks; TCU software error.

How do I fix a U1A04 diagnostic trouble code?

To fix U1A04: Check service history for TCU replacement. Read current VIN from TCU using diagnostic equipment. Compare VIN from TCU with vehicle VIN. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U1A04?

Yes, but get it checked soon

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See also: Russian version · NationStat