VCDS Wiki: Matching Key Fobs to Your Audi A4

This VCDS wiki guide provides step-by-step instructions for matching new radio-frequency remote keys to your Audi A4. This process utilizes a VCDS diagnostic tool and does not cover Immobilizer component matching. Always consult your factory repair manual for specific details related to your vehicle year and model.

Understanding Key Matching with VCDS

Before starting, gather all the key fobs you want to program, including existing ones. You’ll need access to a VCDS interface and software to communicate with your Audi A4’s control modules. The process generally involves two methods: Adaptation and Measuring Blocks.

Method 1: Adaptation Channels

This method uses adaptation channels within the Central Convenience or Central Locking module to program the key fobs.

1. Connect VCDS and Access Module: Connect your VCDS interface to your Audi A4’s OBD-II port and launch the VCDS software. Select [46 – Cent. Conv.] or [35 – Cent. Locking] depending on your vehicle. You can find the correct module using the Ross-Tech application guide.
2. Read Channel 01 (or 21): Go to [Adaptation – 10] and enter channel “01”. In some Audi A4 models, this might be channel “21”. Click [Read] to see the number of currently stored remotes.
3. Enter New Value: Enter the total number of keys you want to program (up to 4) in the “New Value” field and click [Test]. Verify the “Test Value” is correct, then click [Save].
4. Program Each Key: Within 15 seconds, press and hold the UNLOCK button on each key fob for at least one second. You should receive an acknowledgment from the car (e.g., flashing lights, horn beep) as each key is learned.

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Method 2: Measuring Blocks

If Method 1 fails, use Measuring Blocks to program your key fobs.

1. Access Module with Working Key: Insert a working key in the ignition and turn it to the ON position (do not start the engine). Select [46 – Cent. Conv.] or [35 – Cent. Locking].
2. Read Measuring Block Group: Go to [Meas. Blocks – 08] and enter group “003” (or “007” in some vehicles). Click [Go!]. Field 2 will display the number of matched remotes and their memory positions.
3. Program New Key: Lock the car using the new key in the driver’s side door lock. Within 5 seconds, press the UNLOCK button on the new key multiple times to reach the next available memory position (indicated by a “0” in Field 2 of Group 003). The car may acknowledge each press.
4. Verify Programming: Wait 5 seconds, unlock the door with the new key, turn the ignition OFF, and remove the old key. Test the new key by locking and unlocking the car.
5. Confirm with Measuring Blocks: Insert the new key in the ignition, turn to ON, access the module, go to [Meas. Blocks – 08], and enter group “003”. Field 2 should now show the new key matched in the correct memory position.

Clearing Existing Remotes

If necessary, you can clear all matched remotes:

1. Access Adaptation Channel 00: Select [46 – Cent. Conv.] or [35 – Cent. Locking], go to [Adaptation – 10], and enter channel “00”.
2. Clear Remotes: Click [Read], then [Save]. Confirm the prompt to save a value of 0 to Channel 00. This will erase all previously matched key fobs. You’ll need to reprogram all keys using one of the methods above.

Conclusion

Matching key fobs to your Audi A4 with VCDS can be straightforward when following the correct procedure. Remember to consult the Ross-Tech Wiki for detailed instructions specific to your Audi A4 model year. This guide provides a general overview and may vary slightly depending on your vehicle. Always prioritize safety and refer to your factory repair manual for comprehensive information.