Question 1

How long does the Lexus dealer take to replace a key for a 2003 GX?

Accepted Answer

For a vehicle this age, the fob itself is not a current production part, so the dealer experience starts with a parts availability question. If the part is not sitting in their bin, you are waiting on a back-order. After that, you need a service appointment, a tech, and a scan tool session to program the transponder and enroll the fob. Owners posting on GX forums describe the whole process taking anywhere from a few days to over a week once you factor in parts sourcing and scheduling. We carry what this vehicle needs and do the job the same day, wherever the GX is parked.

Question 2

What exactly is a remote head key and why does it need programming?

Accepted Answer

A remote head key is a single unit where the key blade and the fob are built together. You turn it in the ignition like a regular key, but there is a transponder chip inside the head that talks to the immobilizer every time you try to start the car. The vehicle security system checks for a signal it recognizes. If the chip is not programmed to that specific GX, the engine will either not crank at all or it will start and die within a second or two. The remote buttons for lock and unlock are part of the same unit, enrolled separately to the body side of the system. So there are two things that have to be right: the transponder registration and the remote enrollment. A freshly cut blade that has never been programmed will physically turn the ignition and do nothing else.

Question 3

Why does key replacement at the dealer take so long compared to a mobile locksmith?

Accepted Answer

Three things stack up. Parts first: a dealer has to locate and order the correct fob for a vehicle this old, and it is not always on the shelf. Then scheduling: you need a service bay appointment, not just a walk-in. Then the workflow itself: writing the repair order, waiting on dispatch, pulling from parts, finding the right scan tool subscription current. What is genuinely a 45-minute technical job turns into a multi-day event. Mobile means I show up with the part and the tools already loaded for your specific vehicle. The job happens in your driveway or parking lot, same day you call.

Question 4

My 2003 GX starts fine but the remote buttons stopped working. Do I need a whole new key?

Accepted Answer

Not necessarily. If the engine starts, the transponder side of the key is healthy. The remote functions are a separate radio enrollment. First thing to check is the CR1616 battery, and make sure it is actually a CR1616 and not a thinner or thicker substitute someone put in there. A weak or wrong-size cell will kill the remote range before it kills anything else. If a correct fresh battery does not bring it back, the fob may have dropped out of enrollment, which happens on these over time, especially after a battery swap done the wrong way or a dead-flat battery situation. Re-enrolling the remote to the vehicle is a separate step from the transponder and can often be done without replacing the whole key.

Question 5

Can I buy a replacement fob online and program it myself to my 2003 GX?

Accepted Answer

The remote enrollment side has an onboard sequence on this generation, so if you already have a working key, there is a documented procedure to add a second fob without external tools. But the transponder chip still needs to be matched to your immobilizer, and that part requires equipment. So buying a fob online gets you halfway there at best. If you are doing an all-keys-lost situation, no working key at all, the online fob purchase does not help you until a tech with the right tools comes out anyway. Save the research time and call first so we can tell you exactly what the job involves for your specific situation.

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