Can Sc400 1993 Have Key Re-programmed

[tjcooper]

I have seen threads that say that the 1993 SC400 cannot be reprogrammed and a new

key and ECU unit are required. I have had one key reseller tell me that they have

successfully done a re-program on a 1993.

Does anyone have proof positive (done it themselves or seen a unit in a car) that has been

re-programmed? Most of the manuals indicate that 1993 had non-programmable key and

ECU combinations that had to be dealer replaced to get a new key and fob working. Anyone

with DEFINITE information I would appreciate responses. Much thanks.

Ted

[2JZ_SC]

When you buy a key for the older (93) lexus cars. You get one key and a ROM (read oy memory) chip. To replace the key you remove the old ROM chip and install the new one that comes with the key. No programing.

[blues-harp]

When you buy a key for the older (93) lexus cars. You get one key and a ROM (read oy memory) chip. To replace the key you remove the old ROM chip and install the new one that comes with the key. No programing.

I'm an English lit major and, for all my efforts, I'm completely unable to understand this response. Who does what to whom when? When who buys a key from whom under what circumstances? To replace what key? Why would you replace a key you just bought? Install what ROM chip in which key when with what old and new chip? "Oy" memory? Please try again ... your response is 100% incoherent.

[Micah]

ROM means Read Only Memory. It means it cannot be programmed with a newer remote, hence Read Only. As for replacing the key, the car you bought has the remote built into the KEY (a single button behind the Lexus symbol). When you purchase this key (from a dealer), he is saying that you also recieve a chip that you (or the dealer) would install into the car. This allows the car to "talk" to the remote. As it stands now, the car only knows how to "talk" to one remote, the one that you do not have. This would be the one that came with the car when purchased. Newer cars (such as ones purchased in 1996) have newer technology. This newer technology allows one to program a replacement remote without replacing the chip that allows the car to talk to the remote. This type of programmable technology is called EPROM which stands for Erasable, Programmable, Read Only Memory. In short, you can change the way the car talks to the remote with this type of technology whereas with plain ROM memory the only way to change the remote is to change the chip (that tells the car which code to listen for). BTW, memory is the medium with which any computer stores information. Sorry so long winded, but you requested clarification. I hope that I have done this as I have done the best I can as I am not a writer. I see numbers better as I am a Mathematics Major.

I do know one other thing, I was able to reprogram my keyless entry on my car. It is a 1996 SC400. I will post the steps that I used successfully in PDF format.

Here's the PDF. This worked for me.

Pages_from_96_key_fob.pdf

[FemiBoanerges]

ROM means Read Only Memory. It means it cannot be programmed with a newer remote, hence Read Only. As for replacing the key, the car you bought has the remote built into the KEY (a single button behind the Lexus symbol). When you purchase this key (from a dealer), he is saying that you also recieve a chip that you (or the dealer) would install into the car. This allows the car to "talk" to the remote. As it stands now, the car only knows how to "talk" to one remote, the one that you do not have. This would be the one that came with the car when purchased. Newer cars (such as ones purchased in 1996) have newer technology. This newer technology allows one to program a replacement remote without replacing the chip that allows the car to talk to the remote. This type of programmable technology is called EPROM which stands for Erasable, Programmable, Read Only Memory. In short, you can change the way the car talks to the remote with this type of technology whereas with plain ROM memory the only way to change the remote is to change the chip (that tells the car which code to listen for). BTW, memory is the medium with which any computer stores information. Sorry so long winded, but you requested clarification. I hope that I have done this as I have done the best I can as I am not a writer. I see numbers better as I am a Mathematics Major.

I do know one other thing, I was able to reprogram my keyless entry on my car. It is a 1996 SC400. I will post the steps that I used successfully in PDF format.

Here's the PDF. This worked for me.

For a mathematician, you write very well. Thank you for clarifying this matter. I have just bought a 1991 LS400. I noticed that the key and the car do not 'talk' i.e. no central locking function. Do you know the procedure to get the car and the master key talking again? I have put a new battery in the master key.

Femi

[pyccke87]

ROM means Read Only Memory. It means it cannot be programmed with a newer remote, hence Read Only. As for replacing the key, the car you bought has the remote built into the KEY (a single button behind the Lexus symbol). When you purchase this key (from a dealer), he is saying that you also recieve a chip that you (or the dealer) would install into the car. This allows the car to "talk" to the remote. As it stands now, the car only knows how to "talk" to one remote, the one that you do not have. This would be the one that came with the car when purchased. Newer cars (such as ones purchased in 1996) have newer technology. This newer technology allows one to program a replacement remote without replacing the chip that allows the car to talk to the remote. This type of programmable technology is called EPROM which stands for Erasable, Programmable, Read Only Memory. In short, you can change the way the car talks to the remote with this type of technology whereas with plain ROM memory the only way to change the remote is to change the chip (that tells the car which code to listen for). BTW, memory is the medium with which any computer stores information. Sorry so long winded, but you requested clarification. I hope that I have done this as I have done the best I can as I am not a writer. I see numbers better as I am a Mathematics Major.

I do know one other thing, I was able to reprogram my keyless entry on my car. It is a 1996 SC400. I will post the steps that I used successfully in PDF format.

Here's the PDF. This worked for me.

For a mathematician, you write very well. Thank you for clarifying this matter. I have just bought a 1991 LS400. I noticed that the key and the car do not 'talk' i.e. no central locking function. Do you know the procedure to get the car and the master key talking again? I have put a new battery in the master key.

Femi

I also have just bought a 1994 SC400 and replaced the battery but still have had no luck in figuring out how to get it working once again. Any help would be greatly appreciated.

[DaveMcKenz]

ROM means Read Only Memory. It means it cannot be programmed with a newer remote, hence Read Only. As for replacing the key, the car you bought has the remote built into the KEY (a single button behind the Lexus symbol). When you purchase this key (from a dealer), he is saying that you also recieve a chip that you (or the dealer) would install into the car. This allows the car to "talk" to the remote. As it stands now, the car only knows how to "talk" to one remote, the one that you do not have. This would be the one that came with the car when purchased. Newer cars (such as ones purchased in 1996) have newer technology. This newer technology allows one to program a replacement remote without replacing the chip that allows the car to talk to the remote. This type of programmable technology is called EPROM which stands for Erasable, Programmable, Read Only Memory. In short, you can change the way the car talks to the remote with this type of technology whereas with plain ROM memory the only way to change the remote is to change the chip (that tells the car which code to listen for). BTW, memory is the medium with which any computer stores information. Sorry so long winded, but you requested clarification. I hope that I have done this as I have done the best I can as I am not a writer. I see numbers better as I am a Mathematics Major.

I do know one other thing, I was able to reprogram my keyless entry on my car. It is a 1996 SC400. I will post the steps that I used successfully in PDF format.

Here's the PDF. This worked for me.

For a mathematician, you write very well. Thank you for clarifying this matter. I have just bought a 1991 LS400. I noticed that the key and the car do not 'talk' i.e. no central locking function. Do you know the procedure to get the car and the master key talking again? I have put a new battery in the master key.

Femi

You are probably out of luck. There is a test to see if you have any radio signal coming from your key. use the search function on this forum, but you turn your FM radio to some given frequency and see if you get a squeak when you press your key. If you do, then your central locking ROM is bad. If you don't you may have a defective key transmitter.

I just scrapped mine and put an aftermarket keyless entry. Works great.

Good luck

[essie400]

When you buy a key for the older (93) lexus cars. You get one key and a ROM (read oy memory) chip. To replace the key you remove the old ROM chip and install the new one that comes with the key. No programing.

How does one replace the ROM chip? Where is it located?

[TWS]

Micah,

can you please post the instructions for '94 and earlier models? My wife's '94 SC300 keyless lock/unlock remote is not working. I replaced the batteries in 2 keys to no avail... I am guessing they "lost" their programming and need to be reset.

She has the keys with the small button on the front, next to the blade of the key. The batteries are in the handle of the key inside the Lexus symbol.

TIA!

Todd

EDIT: I also sent Micah a PM as I noticed how old this thread is.

[essie400]

Micah,

can you please post the instructions for '94 and earlier models? My wife's '94 SC300 keyless lock/unlock remote is not working. I replaced the batteries in 2 keys to no avail... I am guessing they "lost" their programming and need to be reset.

She has the keys with the small button on the front, next to the blade of the key. The batteries are in the handle of the key inside the Lexus symbol.

TIA!

Todd

EDIT: I also sent Micah a PM as I noticed how old this thread is.

Thanks Todd,

I purchased two brand new keyless entry keys via telephone from the nearby Lexus dealer and at the time I was told that no programming would be necessary. When I dropped by to pick up the keys, voila! :o I was told that there would be an additional labor charge to install the new chip!!! If it's a simple matter of replacing the chip I'd like to tell them to go jump in a lake!

HELP!?!?!?

Jeff

[caramoe]

So how do you program a fob 2006 lexus gs300 2006.

Micah,

can you please post the instructions for '94 and earlier models? My wife's '94 SC300 keyless lock/unlock remote is not working. I replaced the batteries in 2 keys to no avail... I am guessing they "lost" their programming and need to be reset.

She has the keys with the small button on the front, next to the blade of the key. The batteries are in the handle of the key inside the Lexus symbol.

TIA!

Todd

EDIT: I also sent Micah a PM as I noticed how old this thread is.

Thanks Todd,

I purchased two brand new keyless entry keys via telephone from the nearby Lexus dealer and at the time I was told that no programming would be necessary. When I dropped by to pick up the keys, voila! :o I was told that there would be an additional labor charge to install the new chip!!! If it's a simple matter of replacing the chip I'd like to tell them to go jump in a lake!

HELP!?!?!?

Jeff