2000-2003 Lexus RX300 models in the U.S. and Canada use a remote-head transponder key that combines the mechanical blade, an immobilizer chip, and a built-in keyless entry remote. Programming typically has two separate parts: cutting and immobilizer registration of the transponder chip with the vehicle, and onboard programming of the remote-lock/unlock functions using a specific sequence of ignition cycles and door-lock operations. Many aftermarket and OEM-style replacements are available that match the original key’s electronics and FCC ID for these years.
Key types used on the RX300:
remote-head transponder key (integrated key + remote buttons) using Texas ID 4C chip (1999-2003 USA/Canada, including 2000-2003 requested range)
Common fob FCC IDs: NI4TMTX-1 — check the back of your fob; we confirm the exact variant on site.
2000 Lexus RX300
Route verified — exact steps vary by trim/equipment
Route verified as onboard programming (no dealer needed). The sequences below are general route guidance — use them only if your vehicle shows the same prompts and controls. If the prompts don’t match, stop and call us.
Show the programming methods (19 steps)
Preparation Steps
Remove the key
1 Remove key from ignition switch before beginning programming.
Programming step
2 Ensure driver’s door is open and unlocked; ensure all other doors are closed.
Insert the key
3 Insert key into ignition switch, then remove it to start registration sequence.
Wait / timing window
4 Complete the programming sequence steps within 40 seconds or less.
Close the doors
5 Close and then open driver’s door during initial lock/unlock cycle step.
Mode Selection Procedure
Press LOCK + UNLOCK
1 Press door lock switch to LOCK then within one second press to UNLOCK; repeat until door locks have been locked and unlocked 5 times.
Insert the key
2 After completing lock/unlock cycles, insert key into ignition switch for mode selection.
Cycle the ignition ON/OFF
3 Turn ignition switch to ON and back to LOCK (one cycle) within one second the specified number of times to select mode.
5 Remove key from ignition switch after completing specified number of cycles; door locks will cycle to confirm selection.
Transmitter Registration Steps
Cycle the ignition ON/OFF
1 For add, rewrite, or prohibition modes, door locks will automatically cycle 1 (add), 2 (rewrite), or 5 (prohibition) times after mode initiation.
Press LOCK + UNLOCK
2 Press transmitter LOCK and UNLOCK buttons simultaneously for at least 1.5 seconds to begin code transmission step.
Press / hold a fob button
3 Within 3 seconds after simultaneous press, press any transmitter button for at least one second.
Wait / timing window
4 Successful acceptance indicated by door locks cycling one time within 3 seconds after button press.
Cycle the ignition ON/OFF
5 If door locks cycle 2 times, code was not accepted; repeat step within 40 seconds to attempt additional programming.
Completion and Notes
Wait / timing window
1 Registration completes if 40 seconds elapse since ECU response, driver’s door is closed, key is inserted into ignition, or four codes are registered.
Cycle the ignition ON/OFF
2 Confirmation mode causes door locks to cycle 0–4 times depending on number of stored transmitter codes (example: two stored codes = 2 cycles).
Programming step
3 If number of registered codes exceeds four, previously registered codes erased starting with first registered code.
Programming step
4 Use prohibition mode if a transmitter is lost or stolen to erase all existing registered codes.
Route verified — exact steps vary by trim/equipment
Route verified as onboard programming (no dealer needed). The sequences below are general route guidance — use them only if your vehicle shows the same prompts and controls. If the prompts don’t match, stop and call us.
Show the programming methods (20 steps)
Preparation Steps
Remove the key
1 Remove key from ignition switch to begin programming
Programming step
2 Drivers door must be open and unlocked; all other doors must be closed
Insert the key
3 Insert key into ignition switch and then remove it as part of initial sequence
Wait / timing window
4 All programming steps must be completed within 40 seconds or less at specified stages
Close the doors
5 Close and then open drivers door during initial lock/unlock cycle step
Mode Selection and Entry
Press LOCK + UNLOCK
1 Press door lock switch to LOCK, then within one second press to UNLOCK; repeat until door locks have been locked and unlocked five times
Insert the key
2 Insert key into ignition switch after initial cycles to enter mode selection
Cycle the ignition ON/OFF
3 Turn ignition switch to ON and back to LOCK (one cycle) within one second the specified number of times to select mode
5 Remove key from ignition switch after mode selection to complete confirmation code registration and cause door locks to cycle
Mode Functions and Behavior
Cycle the ignition ON/OFF
1 Add Mode: adds a transmitter without erasing existing transmitter codes; one automatic door lock cycle confirms initiation
Cycle the ignition ON/OFF
2 Rewrite Mode: erases all previously registered transmitter codes and reprograms new transmitters; two automatic door lock cycles confirm initiation
Cycle the ignition ON/OFF
3 Confirmation Mode: informs of number of existing transmitter codes already programmed; door locks cycle 0–4 times depending on stored codes
Cycle the ignition ON/OFF
4 Prohibition Mode: erases all existing registered transmitter codes and cancels wireless door lock operation; five automatic door lock cycles confirm initiation
Cycle the ignition ON/OFF
5 Example given: two stored codes equals two door lock/unlock cycles in confirmation mode
Transmitter Registration Procedure
Press LOCK + UNLOCK
1 After mode initiation, press transmitter LOCK and UNLOCK simultaneously for at least 1.5 seconds
Press / hold a fob button
2 Within 3 seconds of simultaneous press, press any transmitter button for at least one second
Wait / timing window
3 Successful acceptance indicated by door locks cycling one time within 3 seconds
Cycle the ignition ON/OFF
4 If door locks cycle two times, transmitter code not accepted; return to previous step within 40 seconds to attempt again or program additional transmitter
Wait / timing window
5 Registration completes when 40 seconds elapse since ECU response, drivers door is closed, key inserted into ignition cylinder, or four recognition codes are registered at one time
Route verified — exact steps vary by trim/equipment
Route verified as onboard programming (no dealer needed). The sequences below are general route guidance — use them only if your vehicle shows the same prompts and controls. If the prompts don’t match, stop and call us.
Show the programming methods (20 steps)
Preparation and Initial Steps
Remove the key
1 Remove key from ignition switch to begin programming
Programming step
2 Ensure driver’s door is open and unlocked; ensure all other doors are closed
Insert the key
3 Insert key into ignition switch and then remove it as part of initiation
Wait / timing window
4 All steps requiring repeated actions must be completed within 40 seconds or less
Cycle the ignition ON/OFF
5 Door lock switch used: press to LOCK then within one second to UNLOCK repeatedly until locks cycle 5 times
Entering Registration Mode
Close the doors
1 After initial lock/unlock cycles, close and then open driver’s door before proceeding
Insert the key
2 Insert key into ignition switch after door open/close sequence
Cycle the ignition ON/OFF
3 Turn ignition switch to ON and back to LOCK (one cycle) within one second the specified number of times to select mode
Remove the key
4 Remove key from ignition switch after completing the required number of cycles
Cycle the ignition ON/OFF
5 Confirmation of registration mode occurs when door locks cycle after mode selection
2 Confirmation mode: door locks will cycle 0–4 times indicating number of transmitter codes already programmed
Cycle the ignition ON/OFF
3 After selecting Add, Rewrite, or Prohibition, door locks automatically cycle once (Add), twice (Rewrite), or five times (Prohibition) to confirm initiation
Press LOCK + UNLOCK
4 During programming, press transmitter LOCK and UNLOCK simultaneously for at least 1.5 seconds, then within 3 seconds press any transmitter button for at least one second
Cycle the ignition ON/OFF
5 Successful acceptance indicated by door locks cycling one time within 3 seconds; two cycles indicates failure to accept
Completion Criteria and Troubleshooting
Press / hold a fob button
1 If new transmitter code not accepted, attempt programming again by returning to the step requiring button press within 40 seconds
Wait / timing window
2 Registration complete when any of the following occur: 40 seconds elapse since ECU response, driver’s door is closed, key is inserted into ignition cylinder, or four recognition codes are registered
Programming step
3 Four recognition codes limit: if exceeded, previously registered codes erased in order starting with first registered code
Cycle the ignition ON/OFF
4 Confirmation mode provides count of existing transmitter codes via lock/unlock cycles
Programming step
5 Use Prohibition mode when transmitter is lost or stolen to erase codes and cancel wireless door lock operation
Year coverage comes from our consolidated vehicle programming dataset. Route-level programming status is reviewed against internal route sheets and available manufacturer, security-access, and professional tool references. Exact button sequences are marked source-verified only when we have year/equipment-specific support; where a year is labeled “route verified, steps vary,” we confirm the exact fob, trim, and prompts before programming. Reviewed for route and safety by Mohammad H. Abdelhadi, ALOA-Certified Master Locksmith.
Year
Route status
Exact steps
2000
Route verified
General guidance
2001
Route verified
General guidance
2002–2003
Route verified
General guidance
Common questions
What type of key does my 2000-2003 Lexus RX300 use?
These RX300 models use a remote-head transponder key that combines the metal key blade, a Texas ID 4C transponder chip, and built-in remote lock/unlock buttons.
Can I program a replacement remote for my Lexus RX300 myself?
The keyless entry portion can be programmed onboard using a specific sequence of ignition and door-lock steps; detailed instructions are typically supplied with replacement remotes.
Do all 1999-2003 Lexus RX300 keys use the same FCC ID remote?
Many sources list remote-head keys for 1999-2003 RX300 with FCC ID NI4TMTX-1, but part numbers and shells can vary by supplier.
Can you program a RX300 key fob without going to the dealership?
For most years, yes - the route is onboard relearn or an OBD tool, both of which a mobile locksmith handles at your location.
Does this program the remote only, or the transponder key too?
It depends on your key type. Tell us your FCC ID and we will confirm.
What if my year says professional programming required?
Those years need a programmer or security access; we bring the tool to you and program it on site.
How much does it cost?
It depends on year, key type, and whether you have a working key. Call (833) 439-8636 for a firm price before we dispatch.
Need your RX300 fob programmed? We come to you, 24/7.
