U0434
Invalid Data Received from Immobilizer Module
2002-2005 Audi A4 3.0L V6
High SeverityNetworkGeneric (SAE)
Description
Data from the immobilizer or anti-theft module is invalid, preventing vehicle operation.
Symptoms
- Vehicle will not start
- Security indicator flashing
- Key not accepted
- Cranking but no fuel/spark
- Immobilizer fault message
Common Causes
- Key transponder weak or failing
- Antenna ring malfunction
- Immobilizer module corruption
- CAN bus interference
- Key not properly programmed
Diagnostic Steps
- Test key transponder signal strength
- Check antenna ring signal
- Attempt key relearn procedure
- Check CAN bus quality at immobilizer module
- Test with known good key
Repair Notes
Attempt key relearn procedure. If key transponder is weak, program new key.
Related Codes
Other Network Codes
- U0001High Speed CAN Communication Bus
- U0002High Speed CAN Communication Bus Performance
- U0003High Speed CAN Communication Bus (+) Open
- U0004High Speed CAN Communication Bus (+) Low
- U0005High Speed CAN Communication Bus (+) High
- U0006High Speed CAN Communication Bus (-) Open
- U0007High Speed CAN Communication Bus (-) Low
- U0008High Speed CAN Communication Bus (-) High
- U0009High Speed CAN Communication Bus Shorted Together
- U0010Medium Speed CAN Communication Bus
U0434 on Other Vehicles
Common Questions
What does code U0434 mean on a 2002-2005 Audi A4?
U0434 stands for "Invalid Data Received from Immobilizer Module". Data from the immobilizer or anti-theft module is invalid, preventing vehicle operation.
What are the symptoms of U0434 on a Audi A4?
Common symptoms of U0434 include: Vehicle will not start, Security indicator flashing, Key not accepted, Cranking but no fuel/spark, Immobilizer fault message.
What causes U0434 on a 2002-2005 Audi A4?
Common causes of U0434 include: Key transponder weak or failing, Antenna ring malfunction, Immobilizer module corruption, CAN bus interference, Key not properly programmed.