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

MPX Body control question

Thread Tools
 
Search this Thread
 
Old Mar 29, 2008 | 05:30 AM
  #1  
fasty's Avatar
fasty
Thread Starter
Driver School Candidate
 
Joined: Jan 2008
Posts: 8
Likes: 0
From: Ontario
Question MPX Body control question

Hi,

I am looking for location in my 2003 RX300 "MPX computer" controlling km/miles display. http://www.cbss.ca/images/eStore/RX300-mpx.jpg

I have US (Miles/Fahrenheit) version and understand that by replacing MPX with metric I can get kilometers and Celsius display. Anybody have and experience or cost involved with this project?

Thanks in advance

Edward
Reply
Old Mar 29, 2008 | 06:24 AM
  #2  
Lexmex's Avatar
Lexmex
CL Community Team
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2004
Posts: 17,338
Likes: 213
From: Miami, Florida
Default

In all my years here, I don't think I have ever seen someone actually go ahead and do it this way, though I am aware of some in Russia having done something similar to what you are describing in order to switch to metric.
Reply
Old Mar 29, 2008 | 06:43 AM
  #3  
fasty's Avatar
fasty
Thread Starter
Driver School Candidate
 
Joined: Jan 2008
Posts: 8
Likes: 0
From: Ontario
Default

Reason I asked is that I seen at eBay that MPX computer is selling in US, he says it comes with instruction and it takes 5 min to do it. He also ask to send old module for exchange.
Reply
Old Mar 30, 2008 | 07:09 AM
  #4  
fasty's Avatar
fasty
Thread Starter
Driver School Candidate
 
Joined: Jan 2008
Posts: 8
Likes: 0
From: Ontario
Default

At least anybody knows where can I find it in my car? I need part number that I can order from Toyota/Lexus dealer.

Edward

Last edited by fasty; Mar 30, 2008 at 07:30 AM.
Reply
Old Mar 30, 2008 | 07:31 AM
  #5  
salimshah's Avatar
salimshah
CL Community Team
25 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2001
Posts: 16,603
Likes: 1,402
From: Austin, TX
Default

I fail to understand why people don't call the dealership/parts department for a part number. The parts over time can be improved and old parts can be retired. There are added advantage that if the part is wrong, the dealer will take it back.
[that is if you choose to order through them ... maybe for a higher price].

I have had excellent service and have witnessed the helpfulness of the parts staff here in Lexus of Austin.

If you ask the members, you run the risk of unintended wrong guidance.

Salim
Reply
Old Mar 30, 2008 | 07:38 AM
  #6  
fasty's Avatar
fasty
Thread Starter
Driver School Candidate
 
Joined: Jan 2008
Posts: 8
Likes: 0
From: Ontario
Default

You are right, but at least I would have better idea what I am talking about when ordering, those module I understand are not very common. Other thing why I would like to know where it is, that I can possibly replace it on my own, but I have to find it and estimate difficulties.

Edward
Reply
Old Apr 3, 2008 | 07:46 AM
  #7  
fasty's Avatar
fasty
Thread Starter
Driver School Candidate
 
Joined: Jan 2008
Posts: 8
Likes: 0
From: Ontario
Default

Originally Posted by salimshah
I fail to understand why people don't call the dealership/parts department for a part number. The parts over time can be improved and old parts can be retired. There are added advantage that if the part is wrong, the dealer will take it back.
[that is if you choose to order through them ... maybe for a higher price].

I have had excellent service and have witnessed the helpfulness of the parts staff here in Lexus of Austin.

If you ask the members, you run the risk of unintended wrong guidance.

Salim
I just got of the phone to my local Lexus part department, they can only suggest to change whole dashboard, $3,000, but he also mention if I come up with part # he would be able to look it up. From my picture I can't really read full number anybody could help to get that number, please?
Reply
Old Apr 3, 2008 | 01:15 PM
  #8  
bob2200's Avatar
bob2200
Driver
 
Joined: Mar 2002
Posts: 1,800
Likes: 13
From: Maryland
Default

Going only by the picture, and my sketch-to-parts-number diagrams (i.e., I could be wrong); it looks like the Multiplex Computer:

99-00 89221-48080
01-02 89221-48031
Reply
ClubLexus Stories

Celebrating Lexus & Toyota from Around the Globe

story-0

Toyota and Lexus Join Mille Miglia For The First Time

 Verdad Gallardo
story-1

Lexus NX 350h: A Fuel-Sipping Secret Hot Hatch???

 Michael S. Palmer
story-2

5 Best & 5 Worst Lexus Daily Drivers

 Joe Kucinski
story-3

Top 5 Hottest Lexus & Toyotas in 2026 (Hardest To Buy)

 Brett Foote
story-4

2026 Lexus IS 350 F Sport Review: The Last of Its Kind Still Rocks

 Michael S. Palmer
story-5

Top 10 Most Confusing Things Lexus Has Ever Done!

 Joe Kucinski
story-6

2026 Lexus ES Review: Lexus Re-Embraces Founding Principles

 Michael S. Palmer
story-7

10 Lexus Bargains That are Cheaper Than a New Toyota RAV4

 Joe Kucinski
story-8

8 Weirdest Things Lexus Has Ever Built

 Verdad Gallardo
story-9

10 Lexus Designs That Have Aged Like Fine Wine

 Verdad Gallardo
Old Oct 23, 2021 | 02:55 PM
  #9  
Wassum3636's Avatar
Wassum3636
Driver School Candidate
 
Joined: Oct 2021
Posts: 13
Likes: 2
From: NEW YORK
Default

Reply
Old Oct 24, 2021 | 10:19 AM
  #10  
salimshah's Avatar
salimshah
CL Community Team
25 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2001
Posts: 16,603
Likes: 1,402
From: Austin, TX
Default

Pardon my ignorance but can some one expand the term MPX body control? Is there an alternative (more commonly used) word(s) for it.

Salim
Reply
Old Oct 26, 2021 | 08:47 PM
  #11  
Margate330's Avatar
Margate330
Lexus Champion
5 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2019
Posts: 11,404
Likes: 1,640
From: FL
Default Body ECU

Originally Posted by fasty
Hi,
I am looking for location in my 2003 RX300 "MPX computer" controlling km/miles display. http://www.cbss.ca/images/eStore/RX300-mpx.jpg
I have US (Miles/Fahrenheit) version and understand that by replacing MPX with metric I can get kilometers and Celsius display. Anybody have and experience or cost involved with this project?
Thanks in advance
Edward
-> Someone would need to verify that the Body ECU(multiplex computer/MPX computer) is responsible for the job of doing this. F/C and miles/km.

Originally Posted by fasty
Reason I asked is that I seen at eBay that MPX computer is selling in US, he says it comes with instruction and it takes 5 min to do it. He also ask to send old module for exchange.
-> Too vague, 5 minutes to do what exactly? Is the seller saying it is a 5 minute job to install it or 5 minute job to change the settings. If he is saying it is a 5 minute job to install it and requiring the old one to be sent in for swap out, the seller is probably selling a used Body ECU reflashed for country/region-needed to change from F ot C.
But, until someone does this and reports success I wouldn't count on an ebay listing as 100% proof this setting from F to C is managed by the Body ECU yet...


Originally Posted by fasty
I just got of the phone to my local Lexus part department, they can only suggest to change whole dashboard, $3,000, but he also mention if I come up with part # he would be able to look it up. From my picture I can't really read full number anybody could help to get that number, please?
-> From what this person is reporting from the Lexus dealer implies that the setting from F to C is done by the ECU's on the circuit boards in the dash cluster behind the speedometer and not the Body ECU- but still inconclusive...

Originally Posted by Wassum3636

-> Pictured above is the location of the Body ECU, in some countries it may be called a "Multiplex Computer" or MPX computer.


Hi members, I am unable to find exactly where the settings from F to C can be changed for our cars. It appears the RX300 has a dedicated Body ECU for the car's interior data network bus.
On the RX330 this has been integrated into the fuse panel/junction box under the steering wheel- I like RX300 design better.
-> If someone ever figures out where the settings can be changed hopefully they will post the info. But as can be seen above, the info on this is contradictory- is it in the Body ECU(multiplex computer) or the dash cluster ECU's? Maybe it's in the Engine ECM, that's always a possibility too.

Here is a pic I made showing how the Body ECU commuicates thru a single wire to the other ECU's such as the Engine ECM, Dash Cluster, Body ECU- any of which can hold the key to the question- where is the settings need changed?


-> Has anyone tried changing F/C and miles/km settings in Techstream? maybe it's that easy, I don't know.



Last edited by Margate330; Oct 27, 2021 at 07:03 AM.
Reply
Old Oct 27, 2021 | 07:15 AM
  #12  
salimshah's Avatar
salimshah
CL Community Team
25 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2001
Posts: 16,603
Likes: 1,402
From: Austin, TX
Default

Thank you Margate330.

If we are talking Km & C then the unit has to be area of sale dependent [European/Canada] and not US.

Since I have not dabbled with these units, I also don't know how and which feature(s) has/have been incorporated into the main ECU. Earlier models of Lexus used dedicated controllers and progressively these have been pulled into central controller and that has necessitated the use of Muliplexing control and data communication on common wires.

Salim

Last edited by salimshah; Oct 27, 2021 at 07:23 AM.
Reply
Old Nov 1, 2021 | 07:02 PM
  #13  
Margate330's Avatar
Margate330
Lexus Champion
5 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2019
Posts: 11,404
Likes: 1,640
From: FL
Default

I can change from Celsius to Farenheight degrees on my soldering iron and basically any modern electronic device including my microwave oven.

-> So why in the world did Lexus think it was smart to make this feature unavailable in a Luxury car blows my mind, there must be a good reason but maybe not- I have no clue...

BTW- the ECM in the RX300 has a 16 bit microcontroller/processor so I'm sure it can handle the math of a simple conversion. lol

Last edited by Margate330; Nov 1, 2021 at 07:05 PM.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
thomax600
NX - 1st Gen (2015-2021)
5
Jun 13, 2018 12:28 PM
Baetke
RX - 1st Gen (1999-2003)
10
Aug 6, 2016 05:59 AM
y7wu
RX - 3rd Gen (2010-2015)
4
May 4, 2016 12:55 PM
tm510
SC430 - 2nd Gen (2001-2010)
3
Mar 23, 2008 06:56 AM
drurywoodson
RX - 2nd Gen (2004-2009)
17
Jun 2, 2003 12:46 AM




All times are GMT -7. The time now is 06:49 PM.

story-0
Toyota and Lexus Join Mille Miglia For The First Time

Slideshow: A five-car lineup spanning more than five decades of Toyota performance and engineering will tackle one of Italy's most celebrated automotive routes.

By Verdad Gallardo | 2026-06-15 16:53:16


VIEW MORE
story-1
Lexus NX 350h: A Fuel-Sipping Secret Hot Hatch???

Slideshow: a quick review of the 2026 Lexus NX 350h F Sport Handling

By Michael S. Palmer | 2026-06-18 14:36:21


VIEW MORE
story-2
5 Best & 5 Worst Lexus Daily Drivers

Slideshow: The 5 best and 5 worst Lexus daily drivers

By Joe Kucinski | 2026-06-15 11:14:58


VIEW MORE
story-3
Top 5 Hottest Lexus & Toyotas in 2026 (Hardest To Buy)

These five Lexus and Toyota models are the most sought-after on the market right now.

By Brett Foote | 2026-06-15 10:47:52


VIEW MORE
story-4
2026 Lexus IS 350 F Sport Review: The Last of Its Kind Still Rocks

Slideshow: the 2026 IS 350 isn't all that new, and that's why we love it!

By Michael S. Palmer | 2026-06-04 14:35:23


VIEW MORE
story-5
Top 10 Most Confusing Things Lexus Has Ever Done!

Slideshow: 10 most confusing things Lexus has ever done.

By Joe Kucinski | 2026-06-04 09:40:55


VIEW MORE
story-6
2026 Lexus ES Review: Lexus Re-Embraces Founding Principles

Slideshow: Our First-Drive Review of the 2026 Lexus ES!

By Michael S. Palmer | 2026-05-29 20:30:16


VIEW MORE
story-7
10 Lexus Bargains That are Cheaper Than a New Toyota RAV4

Slideshow: 10 Lexus bargain that are cheaper than a new Toyota.

By Joe Kucinski | 2026-05-20 10:28:20


VIEW MORE
story-8
8 Weirdest Things Lexus Has Ever Built

Slideshow: From hoverboards to luxury yachts, these are the strangest projects Lexus has ever attached its badge to.

By Verdad Gallardo | 2026-05-16 11:34:36


VIEW MORE
story-9
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