00+ ABS Modulator Serial Numbers Database

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00-05 owners, can you do me a favor and look under your hood and let me know what the first letter of your ABS Modulator serial number is (see example pic below)? I am specifically interested in documenting serial#s and in particular all the letters that a 2000+ unit can start with and I'll explain why below.

91-99 owners, if you're planning to upgrade your ABS modulator with a late model ABS (aka 3rd gen) unit, since they've been discontinued your only option is used. This is a reference thread made in an effort to help confirm that the used unit you're buying is (a) for an NSX and (b) whether or not it will be compatible with TCS. Many here have experienced this upgrade as one of the most noticeable mods that a 91-99 owner can do to their car that significantly enhances the drive and safety aspect.

The NSX, NSX-R and S2000 modulators look identical along with other Honda ABS units. As sellers list either new, used, pulled units (from salvages) and/or sell from overseas, if the Honda barcode sticker on the unit itself has been removed, damaged, or becomes illegible, I'm hoping that referencing the serial#, which is permanently etched into the top-side of the black plastic housing, will be a way to confirm which model modulator it is.

I've been gathering serials from units I've seen in person or for sale online and hope to populate a list to help figure out what any ranges might be. Being that this will have an ongoing learning curve, I apologize ahead of time if any mistakes/bad assumptions are made. This could turn out similar to the snap ring issue where we learned there was no relationship to the VIN and transmission# but I'm hoping that's not the case. I plan to update this post as new info is gathered and hope this might be a collaborative effort so if you're willing to help please pm me or post your serial# (etched into the housing and starts with a giant letter) of your 2000+ unit. Thank you!

Time for a big bowl of serial...

2000+ NSX USDM part# 57110-SL0-Z03
Sticker#
(on white label on black plastic housing) 57105SL0 010
Serial# (etched on black plastic housing)
H OSO5 - OOO4 HO1 (confirmed late model NSX ABS by Eric B.)
H ???8 - OOO4 HO1 (confirmed late model NSX ABS by MotoIQ)
H 2H26 - 1O17 HO1 (confirmed late model NSX ABS by Syndicate)
H 4BO3 - OOO7 HO1 (confirmed late model NSX ABS by Truc D.)
H 3F19 - OOO1 HO1 (confirmed late model NSX ABS by MotorMouth93)
H 9T1O - O55O - HO1 (confirmed late model NSX TYPE-S ABS by NZNick)
L 2O27 - OO63 LO1 (unconfirmed - for sale from Japan)

*Current assumptions:
- Any serial# beginning with an "H" is a bona fide late model NSX ABS modulator and is compatible with TCS
- Any serial# beginning with "L" is unknown but have been seen listed for sale as late model NSX ABS modulators BUT also listed as not compatible with TCS because it was "removed/disabled" according to sellers in Japan. If anyone has any more info on "L" serials that would be very helpful.


Note: It's important when searching for this part to know that the number on the ABS modulator housing sticker, 57105SL0 010, is not the part number even though it looks like one and is not in the Acura/Honda database. You may still, however, get some hits searching by that as the seller might only have this number to go off of when listing it for sale as the box (which has the red/white actual part# sticker on it) is probably long gone. If the plastic housing sticker also happens to be missing/removed/illegible you have nothing left to go off of to identify the unit other than the serial number (which is one of the main purposes of this thread).

2002+ NSX-R JDM part# 57110-SL0-N21
Sticker#
(on white label on black plastic housing) 57105SL0 N10
Serial#
(etched on black plastic housing)
AU 7S1O - OOO1 LOAAA (confirmed late model NSX-R ABS purchased in Japan in 2021 by Kozuchowski)
AU 3F18 - OO11 LOAAA (confirmed late model NSX-R ABS by gotjnco, see pics below)
AU 3F18 - OOO5 LOAAA (confirmed late model NSX-R ABS purchased in Japan in 2024 by Kozuchowski)

*Current assumption:
- Any serial# beginning with an "AU" is a bona fide late model NSX-R ABS modulator and is compatible with TCS. The irony is Type R's did not come with a TCS unit but if you plug this modulator into an NSX with a working TCS unit it functions which could mean R modulators contain similar internals as the "H" serials above but were adjusted for more aggressive driving/brake bias.


Note: It's important when searching for this part to know that the number on the ABS modulator housing sticker, 57105SL0 N10, is not the part number even though it looks like one and is not in the Acura/Honda database. You may still, however, get some hits searching by that as the seller might only have this number to go off of when listing it for sale as the box (which has the red/white actual part# sticker on it) is probably long gone. If the plastic housing sticker also happens to be missing/removed/illegible you have nothing left to go off of to identify the unit other than the serial number (which is one of the main purposes of this thread). The official Acura/Honda part# for a Type-R modulator is 57110-SL0-N21 and is ONLY on the box (see pics down below).

S2000 00-03 (AP1) part# 57110-S2A-J51
Sticker#
(on white label on black plastic housing) 57105S2A J50
Serial#
(etched on black housing)
C 2H14 -1669 CO1 (confirmed S2K)
C 3F2O - O5O9 CO1 (confirmed S2K)
C 3FO6 - OO2O CO1 (confirmed S2K)
C 2B11- O288 CO1 (confirmed S2K)
C 3BO7 - O463 CO1 (confirmed S2K by Honcho)
C 3KO2 - OO31 CO1 (confirmed S2K by tskkhera)
D 9FO6 - OO9O DO1 (confirmed S2K)
D 9H18 - OO5O DO1 (confirmed S2K)
D 9H29 - O3O? DO1 (unconfirmed S2K)
D 9N16 - O258 DO1 (confirmed S2K)
D 9H29 - O3O4 DO1 (confirmed S2K by mogoraug39)
K 1C14 - O676 KO1 (confirmed S2K by Hirose1117)

*Current assumption:
- Any serial# beginning with "C" "D" or "K" is an S2K ABS modulator that will work on an NSX but is not compatible with TCS.


OTHERS (look like it but aren't)
A 1A25 - O574 AO1 (unknown)
AA 3BO7 - 1O49 AA1 (confirmed 03-04 RSX by i am-motors) *note how close this is to an NSX-R serial
B 9NO9 - OO4O BO1 (unknown)
E 9VO9 - OO4O EO1 (confirmed Honda Insight ZE1)
U ???? - 2O19 UO1 (confirmed Honda Stream, confirmed by Kozuchowski)

*Current assumption: any serial# beginning with a "A" "B" "E" or "U" is not compatible with NSX nor TCS ... i.e. do not buy even though it looks like an NSX ABS.

"?" in serial #'s indicates unable to make out the #'s as they are thinly etched onto the plastic housing and the lighting has to be just right

Example 1 - at the time of this posting, there's a late model ABS listing on ebay [LINK] titled as an NSX ABS with serial K 1C14-0676 KO1. I reached out to the seller and the part# is not available and the sticker removed. After specifically inquiring I was also told that "the TCS has been disabled" on this unit. I reached out to the seller again and asked specifically if he would tell me where this unit came from and he informed me it's from an S2000 in Japan and have updated the data list above. It is unfortunate that the listing title is misleading.

Example 2 - at the time of this posting, there's a late model NSX/S2000 ABS listing on Yahoo Japan [LINK] with the serial C 2B11 - O288 CO1. The "C" serial prefix belongs to S2K's and in this case the black plastic housing sticker 57105S2A J50 confirms that. Therefore purchasing this unit, while compatible, will result in no TCS functionality and is not an NSX modulator even though it's listed as one in the title.

Example Serial # D 9N16 - O258 DO1
abs_serial_no.jpg


Example of NSX-R ABS Modulator markings
Serial# (this example starts with AU 3F18 OO11 LOAAA)
NSX-R_modulator_serial.jpg

Box sticker# (note: this is also the part# in the Acura/Honda database)
NSX-R_box_number.jpg


Housing sticker# (note: this is not the part number even though it looks like one and does not show up in the Acura/Honda database but still is a valuable authentication indicator if present)
NSX-R_housing_sticker_number.jpg
 
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Here's mine for your database. Confirmed AP1 unit. S/N 5710-5S2A J50
Thanks Honcho! Would you mind also providing the seriel # on the top side of the black housing next to "NISSIN", I need to know what letter it starts with (probably C or D but could be something else close to that). Thanks!
 
Thanks Honcho! Would you mind also providing the seriel # on the top side of the black housing next to "NISSIN", I need to know what letter it starts with (probably C or D but could be something else close to that). Thanks!
I didn't see anything but just went out to the car and looked again and wouldn't you know! Starts with C.

C 3B07 0463 CO1

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Mine came out of the 02+ NSX-R box
 

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Oh, its so good that someone brought up this topic
57110-SL0-N21 BOX (57105SL0 N10) on Sticker - Serial AU 7S10-0001 L0AAA (Bought in Japan in 2021)
 

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@gotjnco I recently found this active Japan auction listing [LINK] for an NSX-R ABS (~$3600 usd) which has the same serial number as your unit. Perhaps the seller has more than one and is just reusing the same pic or the serial #'s can repeat (doubtful) vs. be unique.
 
I have an 02-05 NSX modulator that I purchased brand new shortly before they were discontinued. PN 57110-SL0-Z03 and serial H3F19-0001-H01

Somewhat related, I purchased an S2K unit on Ebay a while back and pried it open to see if it might be possible to reprogram or replace the CPU to match the NSX programming, and unfortunately it is not.
 
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The programming would have to be extracted from an NSX modulator which is read-protected. Bypassing read protection on an MCU typically involves paying a company in China a few thousand dollars or more to invasively extract the code, destroying the original chip in the process. I also was not able to find a source for new, blank processors and the existing ones are not rewritable.
 
The programming would have to be extracted from an NSX modulator which is read-protected. Bypassing read protection on an MCU typically involves paying a company in China a few thousand dollars or more to invasively extract the code, destroying the original chip in the process. I also was not able to find a source for new, blank processors and the existing ones are not rewritable.
That's cool that you took one apart to discover that. After looking inside and seeing the general CPU layout, do you think it's possible that Honda could have made some modulators that were not read-protected but also not for sale only to be used by Honda Racing, for example, with the ability to tune for racing conditions?
 
Highly unlikely. Any company with competent engineers isn't going to leave IP like that exposed regardless of who is "supposed" to have access to it. If it's tunable, there would be a small region of memory where the tuning parameters are stored separate from the actual programming that uses them.

We were only able to get at the OBD1 ECU code because the processor is so archaic (mid 80s technology) that it doesn't support any sort of code protection, whereas the ABS modules are far more modern.
 
another one from Acura NSX 2000
Thanks! Knowing that the pre-02 units also start with "H" is good to know so it appears that H serials range from 2000-2005.

And thanks for including the sticker on the plastic housing ... it only differs by one character from regular ABS to Type-R ABS (57105SL0 010 vs 57105SL0 N10). Since a 2000 unit's serial starts with "H", then depending on what country as the years may differ (see below) I guess it is possible that a 3rd gen '99 ABS modulator unit (again, depending on where it's from) can be used to upgrade (see below what Kaz posted regarding the various ABS setups or full discussion here) ...

"On our NSX, there are at least 6 different ABS setup through its production years.

The 1st gen. up to certain VIN on 91/92 models.
The 2nd gen. 91/92-96 models with original size brake calliper/disc.
The 2nd gen. 92/93-95 models for Type-R using the same software as above but different piston spring setup. Despite using the same software, the weight distribution, chassis setup, pad, etc were different.
The 2nd gen. 97-99 models with different piston spring setup and different software setting for the introduction of larger brake caliper/disc.
The 3rd gen. one body solution on 99/00-05 standard models.
The 3rd gen. one body solution on NSX-R 02-05 models with different software setting from above.
(Please note that the definition of the Year model is different from country to country and also the introduction of the 2nd gen. ABS was not exactly at the same time across the world so please take these into your consideration.)"
 
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From my JDM Type S - built late 1999:

H 9T10-0550-H01
57105-SL0-010

Photos are very difficult in a RHD car with the hard lines in the way! Couldn’t get a clear photo of either the etched serial number or the label, so had to take many and piece them together to read the numbers…
 
From my JDM Type S - built late 1999:

H 9T10-0550-H01
57105-SL0-010

Photos are very difficult in a RHD car with the hard lines in the way! Couldn’t get a clear photo of either the etched serial number or the label, so had to take many and piece them together to read the numbers…
Thank you for all that effort! Updated the database. You mentioned built late 99, does that mean you have one of the 99 3rd gen ABS units or did you acquire that at a later time?
 
Thank you for all that effort! Updated the database. You mentioned built late 99, does that mean you have one of the 99 3rd gen ABS units or did you acquire that at a later time?
The car is all original, so came with the September 1999 Minor Model Upgrades, which included the 3rd generation ABS.
As I have said before (or elsewhere maybe) this was one of the criteria for choosing this car - I spent 3 years looking for the exact spec of NSX - Type S, not red, non-PAS, non-airbag,..
 
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