alishmee

So when I bought my 2004 A6 2.7t I lost the original key fob. I've been using the Valet Key ever since. I finaly bought a new remote and key and programmed it to my car. So the key lock, unlocks, panics, and opens the trunk. But when I try starting the car with the key it starts then turns right off and the orange key light begins blinking in the cluster. Now I hear this is an immobilizer problem. Is there a way to reset the immobilizer rather than having to go to the dealership? I hear there's a way through the ignition or the driver's side door lock.

RMsALFA

I know that this will happen when the battery starts to die in a keyfob "learned" by the car. I use it as a reminder to change the fob battery.

Yes, in most immobilizer systems, the car must "learn" a new fob.

alishmee

But this is a brand new key. So how do I make the car "learn" the new fob?

radhaz

I've never done this, but it might be what you need.

http://www.ross-tech.com/vag-com/car...-matching.html

alishmee

So ill need to find a vag com...

Mr. Timewise

The "remote control key" you have is made of three important parts:

1. The metal key blade that has been cut to lock or unlock the doors, trunk, and glove box, as well as to turn in the ignition. The metal key is likely a spring loaded hinged mechanism. (A valet key will lock or unlock the doors and turn in the ignition, but probably will not work in the glove box or trunk. In an Avant, the valet key also works in the rear hatch. An all plastic emergency key which is often supplied with a new car should lock and unlock all key locks, as well as turn in the ignition.)
   
2. A radio frequency (RF) transmitter which runs on a replaceable lithium battery. The remote control functions of the transmitter are activated when you depress the buttons on the remote. This pushbutton/RF/battery section of the remote key can be disconnected from the mechanical key section, and the remote features will operate without the mechanical key anywhere nearby.
   
3. An internal, very small, RFID (Radio Frequency Identification) "tag" which is activated by an electrical/magnetic field produced by an excitation coil within the ignition switch. This excitation coil produces an electrical/magnetic field which makes the RFID emit a coded response. This coded response is sensed by the same excitation coil. The code is then interpreted by the instrument cluster immobilizer electronics. If the immobilizer recognizes the code as one which has been mated to the car, the engine is allowed to run. If the code is not recognized, the engine is shut down moments after it is started.

The RFID tag is in the shape of a small gelatin capsule. It is actually made of glass, however, and contains several very small electrical components. It is located next to the hinge point in the remote control key. In the valet key, the RFID tag is molded into the plastic handle. In the plastic emergency key, the RFID tag is either molded into the plastic key when it was formed, or it resides in a compartment that is accessed by separating the key handle into parts. If you look very closely at the plastic emergency key you may be able to see a slight irregularity near the handle of the key where the RFID tag is located, or that the handle is made of two halves. (You can occasionally find an uncut plastic emergency key on eBay which has a handle that splits in half, allowing you to insert a new RFID tag.)

As mentioned, the RFID tag in the remote control key is near the metal key hinge. It is glued into a small chamber which is inside the plastic.

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The RF functionality of a new remote control key can be programmed via the methods outlined in the owner's manual. This will allow the RF remote control section of the key to lock and unlock the doors, open the trunk, and activate the panic alarm.

But without special instrumentation you cannot program the car's immobilizer to accept the RFID tag within any key.* In fact, as the immobilizer systems have evolved Audi/VW have made programming the car's immobilizer more difficult for everyone. Coding a car's immobilizer to recognize new RFID tags is almost impossible unless you visit the dealer, and even the dealer has little information on the procedure because the steps are automatically execute by a computer connected to Audi's headquarters. Unfortunately, unless the immobilizer recognizes the RFID tag coding emitted by a key as being valid for that vehicle, the car's engine will not be allowed to continue running after it initially starts, and the engine will be shut down within a second or so.

Just for fun, you can try this...it may work as an interesting temporary solution:

Use a piece of tape to stick your fully operational valet key to the underside of the steering column as close to the ignition switch as possible. This will place the RFID tag in that key within range of the exciter coil for the immobilizer. Then use your newly cut key (the one whose RFID tag has not been paired with the immobilizer) to start the car. If the engine continues to run, it is probably because the RFID tag in the valet key was near enough to the exciter coil and the immobilizer accepted the valet key's code as valid.

You might also find that once the engine has actually run for several seconds (because the valet key's RFID was accepted by the immobilizer) that you can remove the valet key from below the ignition switch. The engine should run just fine until you turn off the ignition. At that time you'll once again need to hold the valet key next to the ignition switch when using the "unpaired" remote key.

And as always...YMMV

:-)

*Actually, this is mostly true. There have been numerous changes over the years in immobilizer methods. Read the information presented by Ross-Tech regarding the various immobilizer systems and the possible methods you MAY be able to program the immobilizer to accept the RFID tag in new keys.

99a401a6

Hey guys I bought 2 uncut switchblade keys for my 2001 a6 had them cut after I programmed them to lock and unlock and it would start that car for 1 sec then shut off so I tried placing the valet key by the ignition nothing worked then I placed the vallet key up under where you tilt your steering wheel between the Hanse and collomand bam it worked .. Only negative thing is the blinking key light on the dash ... Here is the instructions how to program the locks only.. DIY: How to program your Audi flip key fob.

Prospeeder

If you have immobilizer you cannot just program the key easily. Some software, NOT ross tech, can force the pin code password from the instrument cluster, then you could use vag com, use the pin you got and program the keys. Otherwise dealer visit.

The keyless entry system is totally separate than the immobilizer. So programming your fob has no effect on it not starting the car.

johnkk

Good valet key trick. Nice McGiver.

jcman

It is interesting but not a new trick, most remote starter kits use the cars RFID spare key in a box/module under the dash to over ride the IMMO for keyless starting.