Notices
RX - 1st Gen (1999-2003) Discussion topics related to the 1999 -2003 RX300 models

Problem with master key

Thread Tools
 
Search this Thread
 
Old Jan 30, 2016 | 10:43 AM
  #1  
brianjb's Avatar
brianjb
Thread Starter
Driver School Candidate
 
Joined: Jan 2016
Posts: 3
Likes: 0
From: CA
Default Problem with master key

The screw in my master key fob of my 2002 RX300 fell out and I lost the transponder. I have used the valet key since then. I purchased a new transponder this week, inserted it securely in my old master key case and successfully activated it. It opens and shuts the doors remotely. HOWEVER. I discovered that the old master key will not start the car. I can manually unlock the door with it but when it is inserted in the ignition the security light does not go off. The engine turns over but the car wont start.

1) Does it need the original transponder to work?
2) Can I pair it with the new transponder in some way?
3) Does the dealer have to do this?

Thanks for any help with this puzzling problem. I apologize if it is covered elsewhere but I could not find any reference to it.
Reply
Old Jan 30, 2016 | 11:07 AM
  #2  
JAB's Avatar
JAB
Instructor
 
Joined: Jan 2006
Posts: 1,016
Likes: 22
From: Virginia
Default

Yes, what you lost also includes an immobilizer. Not sure whether you can program your car to recognize it or not; someone here must know.
Reply
Old Jan 30, 2016 | 12:46 PM
  #3  
brianjb's Avatar
brianjb
Thread Starter
Driver School Candidate
 
Joined: Jan 2016
Posts: 3
Likes: 0
From: CA
Default Additional info

I can still start the car with the old valet key. It's the master key that doesn't work in the ignition. Works in door lock as I said.
Reply
Old Jan 30, 2016 | 01:21 PM
  #4  
salimshah's Avatar
salimshah
CL Community Team
25 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2001
Posts: 16,559
Likes: 1,385
From: Austin, TX
Default

Jab diagnosed it right.

The shell and the cut of the key does not make it the master key. The magnetic slug's field signature makes it a master key if it is registered as such in the ecu.

Withe the loss of the slug, unfortunately you have lost the master key.

Valet key has the slug too, but for it to be a valet key, the ecu has the signature saved as valet and the cut of the key will not operate certain locks.

More information can be found in the sticky .. having problems start here sticky.

Salim
Reply
Old Jan 30, 2016 | 02:18 PM
  #5  
brianjb's Avatar
brianjb
Thread Starter
Driver School Candidate
 
Joined: Jan 2016
Posts: 3
Likes: 0
From: CA
Default Thank you

Thank you Jab and Salim. What is strange is that I was able to use the key and shell to program the car to accept the new transponder - in the role of the master key. That's what threw me I guess. Is there some way I can get the new transponder paired with the old key? Can the dealer do this?
Reply
Old Jan 30, 2016 | 05:35 PM
  #6  
salimshah's Avatar
salimshah
CL Community Team
25 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2001
Posts: 16,559
Likes: 1,385
From: Austin, TX
Default

I would always recommend that folks visit the dealership. You never know that the key you think is valet, may be master.

Information on the net (including my posts) may not be correct. Visit the dealership, get your vehicle washed, enjoy the refreshments and browse through the new models on the floor. . Dealers want you there.

Salim
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
natedahms
GS - 2nd Gen (1998-2005)
19
May 15, 2018 02:47 PM
tarzan17
RX - 1st Gen (1999-2003)
25
Aug 30, 2014 08:58 PM
stevenmoua
RX - 2nd Gen (2004-2009)
1
Mar 5, 2012 09:55 AM
dsouthmia0
IS - 1st Gen (2001-2005)
4
Jul 26, 2011 12:35 PM
RelaxJoe
GS - 2nd Gen (1998-2005)
17
Jun 17, 2004 08:29 AM




All times are GMT -7. The time now is 01:32 AM.

story-0
10 Lexus Designs That Have Aged Like Fine Wine

Slideshow: Some luxury cars chase trends, but these Lexus models look better now than they did when they first rolled into showrooms.

By Verdad Gallardo | 2026-05-06 17:58:29


VIEW MORE
story-1
8 Tips for Improving Your Hybrid or Plug-in Hybrid's Efficiency!

Slideshow: How to Get the Best Fuel Economy with a Hybrid and Plug-In Hybrid!

By Michael S. Palmer | 2026-05-05 20:54:44


VIEW MORE
story-2
10 Best Lexus Models No One Remembers

Slideshow: 10 best Lexus models no one remembers.

By Joe Kucinski | 2026-05-05 17:33:28


VIEW MORE
story-3
TRD Off-Road Premium: Best 2026 4Runner, Except This One Thing

Slideshow: diving into 4Runner TRD Off-Road Premium's pricing, performance, fuel economy, features, and amenities!

By Michael S. Palmer | 2026-04-23 13:09:18


VIEW MORE
story-4
Top 10 Lexus & Toyotas to Drive Before You Die!

Slideshow: the 10 Lexus and Toyota vehicles you need to drive before you die.

By Joe Kucinski | 2026-04-23 10:34:24


VIEW MORE
story-5
Top 10 Lexus/Toyotas With The LEAST 5-Year Depreciation

Slideshow: Top 10 Lexus/Toyota models with the lowest 5-year depreciation rate.

By Joe Kucinski | 2026-04-08 12:19:06


VIEW MORE
story-6
Lexus LC500 Convertible Auction: A Preview of Rising Values?

The LC hasn't even disappeared from the Lexus lineup yet, and we're already seeing signs of an explosive market.

By Brett Foote | 2026-04-06 09:25:02


VIEW MORE
story-7
GX 550 vs TX 550: Best 3-Row Luxury Lexus Family Hauler

Slideshow: comparing the pricings, specs, power, fuel economy, fun-factor, and features of the GX 550 Luxury+ and TX 550h+ Luxury.

By Michael S. Palmer | 2026-03-19 13:44:11


VIEW MORE
story-8
9 Best Lexus Models You Can Buy for Half Price (And 1 You Shouldn't!)

Slideshow: 9 best Lexus models you can buy for half price and 1 you should avoid

By Joe Kucinski | 2026-03-19 12:01:07


VIEW MORE
story-9
2026 Lexus NX Buyer's Guide: Models, Features, Prices & More!

Here's everything you need to know about the latest NX.

By Brett Foote | 2026-03-19 11:56:59


VIEW MORE