Today at Atelier Kaz - ex-Honda R&D, F1, Indy/CART engineer

May i ask what is the part number of modulator. Thanks.

I bought a complete conversion kit from SOS for RHD NSX but i ran into problem with the ABS light staying on after the conversion and the ABS is not work too. I am hoping you can help with your sucessfully conversion. The harness from SOS look different than the one from KSP. Also SOS mentioned the modulator i got is from NSXR.

Hi, EK4 hatchback.


You can find the parts list in my other post below;

http://www.nsxcb.co.uk/showthread.ph...2646#post72646

This is also located in the ‘Brake’ section of my ‘NSX Technical and Service Information Index’ thread that can be found at the right side of my Blog page.



The modulator that I used is 57110-SL0-Z03 as you can see in the above list.

If you used the one for 2002 NSX-R (02-R), then the last 3 digits of the parts no is –N21.


You can use 02-R modulator with the standard brake booster and master cyl but strictly speaking, you should be using the 02-R spec booster (which automatically requires 02-R master cyl, which will then automatically require specific brake pipe U & V) as the 02-R ABS tuning is designed based on the sharper assist increase by this specific booster.

I was also told that 02-R ABS will allow the driver to have more control over the tyre locking than the normal one.


As far as I know, SoS is buying the ABS upgrade loom from west part of Japan.

As I have never bought this loom from SoS or from this company in Japan, I don’t know the loom schematic but I presume there should be some description on the installation manual regarding the required modification to the pinout of the loom depending on your year model/spec.


ABS circuit was changed several times during its production including the logic on how to trigger the ABS warning light so you will need to find the correct circuit for your NSX.


As I don’t know the detail of your loom, best to contact SoS.

If it is related to the logic of ABS warning light, it should be just a matter of changing the position of single or a few terminals at the connector(s).

Although I have never bought the parts from them, there are lots of good feedback on NSX Prime so should be able to support you.


While ABS warning light is On, you won’t be able to have ABS.


As in this Blog, it is not so common but there is a slight chance of ABS modulator failure from new.

Kaz

Hi Kaz, i appreciate your reply and i am still waiting for some useful reply from SOS about my issues.

The ABS modulator that i received with part number: 57105SL0 N10 written so it is different than the one you mentioned. I think the problem is with the harness or the modulator since all other parts are quite straight forward. As the brake is working normal except no ABS. I have brake test last week to confirm it, stopping from about 30 mph to a complete stop. I had a friend watching outside the car and from the test both front wheels lock up from 30 mph to stop but the rear wheels seem to have the ABS working since it didn't lock up (it seems the rear wheels locked once and it rolls again).

I used a DMM to checked all the pins in both side of the connectors, so i know what the pins response to what signal from the US service that i got. But i have no information about new modulator pins out. Could the NSXR ABS modulator pin out different than regular NSX ABS modulator? Also i am afraid the RHD wiring is different than the LHD wiring in the harness, do you have any idea? If you don't mind me asking, did you check out the pins on KSP conversion harness? Thanks. I might have to order the harness from KSP instead of using the SOS harness but this would be the last thing i would do.

Thanks again
Keno

Hi, Keno.

What is the spec of your NSX?
For example, the year model?


Unlike the Classic ABS, the upgraded modulator is the same for both the RHD and LHD NSX.


Therefore, the pin out at the ABS modulator is the same for any NSX including the 02-R.

The different part no is for the software code difference.

02-R uses different ABS tuning setup.


All 8 brake pipes are different between RHD and LHD.


The two Orange connector inside the cabin that used to be connected to the original (Classic) ABS controller will have small difference on the pin out depending on the spec and year model of the NSX.


Because of this, you will need to either select the appropriate wiring connection or change the pin out depending on the spec of your ABS upgrade loom.


As far as I know, SoS loom may require swapping of the pin out at the [RELAY] connector for the ABS warning light circuit depending on the year model of your NSX.


Did you see anything in the installation manual from SoS regarding the possible requirement on the pin out modification at the RELAY connector?


You may want to take the photo of the RELAY connector from the direction looking INTO the WIRE side and NOT from the terminal side so that I can understand the pin out and wire colour used.


With the KSP loom, we need to arrange the wiring connection and relay in three different ways for the exact reason.



In Japan, these companies sold more than 600 ABS Upgrade loom.

I never heard any failure with the one from KSP and based on the feedback on the Japanese Forum, it is very unlikely to have failure on the loom from these suppliers and I think SoS is buying it from one of them.


Lots of people are misunderstanding the operation of the ABS.


ABS does NOT prevent the tyre from locking.

Instead, it controls the brake pressure to meet the targeted slip rate at each tyre.

The locking between the front (understeer) and rear (instability) tyre has different meaning so the tuning is different.

Therefore, quite often, the ABS may allow tiny amount of lock at a cetain tyre depending on how the tartgeted slip rate were mapped.

Under normal driving condition, most of the time, the max stopping power or stopping grip is generated when the tyre has just started to slip but the rate will be greatly affected by the load.



The brake test you carried out is not conclusive.

You don’t need your friend to monitor the tyre movement, you don’t need 30mph for the brake test and you don’t need to come to a complete stop.


While the tyre is still cold, just try the same test even at lower speed when/where it is safe to do so.

If your ABS is working, you will get noticeable kick back at the brake pedal before the car comes to a complete stop.


Reaction time and control of the upgraded ABS is so fast and delicate that you will notice significant difference in the kick back speed and the strength compared to the classic ABS.


The upgraded one feels like higher frequency (faster reaction time) but with milder kick back (faster reaction time with delicate control).


So, if you get the kick back at the brake pedal but your ABS warning light stayed ON, then your upgraded ABS is working perfectly fine and just the ABS warning light logic is reversed.


This should be easy to fix by modifying the pin out at the relay connector of your SoS loom.


If you didn’t get even a single kick back at the pedal, your ABS was indeed not working and the ABS warning light was true.


If that is the case, I’ll try the following first.

1. Read the ABS error code.

2. Follow the specific procedure to erase the error code on the upgraded ABS.
You can’t erase it by disconnecting the battery or pulling out the fuse.
You must follow the procedure described in the manual which will involve the brake pedal, IG switch, SCS, etc.
Once done, put ABS SCS terminal to how it was (i.e. disconnect it from GND level).

3. After erasing the error code, turn the IG sw ON but do not start the engine.

4. As soon as the IG sw is ON, the ABS warning light should come ON for about 2sec and then OFF.

5. Turn the IG sw further clockwise to start the engine.

6. As soon as you release the key to let it back to IG ON position, the ABS warning light will be ON for about 2sec and then OFF.

7. If the ABS warning light stayed ON even after 2sec at No.4 and/or No.6, the system failed during the initial diagnosis mode.
Read the error code and ignore the procedure #8 & 9 as you won't have ABS any way.

8. Drive as usual to cover most of the driving condition including some ABS exercise.

9. If you get the ABS warning light, read the error code again (if any).

I think this is enough for the time being.

Kaz

Hi Kaz,

Thanks for the details explanation!! Learning alot!

- My NSX is 1992 MT RHD (export version with headlight washer + rear long license plate bumper).

- The SOS installation manual did not mention, the need of swaping wiring.

- Here is the picture of the relay wires side
http://www.nsxcb.co.uk/attachment.ph...5&d=1311265656

- Thanks for the ABS explanation. During my brake tests, i did once feel there is a very small kick on the brake padel. But i did see smoke from locking up the tire so i am not quite sure. I am hoping it just the ABS light problem due the wiring. Please help check the above picture and see if that lead to any solution. If you have more pictures please let me know. Thanks!!

- I don't know how to read the ABS error code since i don't have the +2000 service manual. Also SOS do not provide any information on diagnostic. But the harness does have 2 wires which is said to be diagnostic. I hope it just the wire swaping, if not i would need more details about this diagnostic. Thanks.

Hi, Keno.

From your comment, it is not clear whether your ABS system is operating fine (but with the warning light in reversed logic) or your ABS is disabled because it detected some issues.


It is important to know what happens to your ABS warning light when you turn the IG sw to ON position.

When IG sw is in ON position, lots of lights on the dash will come ON and it is one position just before starting the engine.

Regarding the ABS warning light;

Q1: Does it turn ON immediately when the IG sw goes into ON position?

If so, does it stay ON for about 2sec and then goes OFF?
Or, does it continuously stay ON over 2sec ?

Q2: Does it stay OFF for about 2sec when the IG sw goes into ON position and then comes ON afterwards or stays OFF forever?

Thank you for the photo of the RELAY connector.

Without knowing the answer to Q1 and Q2 above, it is best not to mention about the pin out modification at this stage although it is very simple.


If your answer to Q1 is ‘yes’ for the first question, then your ABS warning light is in correct logic and it seems that the ABS brain detected some issues on your system and triggered the warning light.


You can download the manual, follow the procedure below to read and reset the error code.


If your answer to Q2 is ‘Yes’, then your ABS warning light logic is reversed and trying to read the error code may confuse yourself because the system may be working perfectly fine or it may show you the wrong code.


Please download the Workshop Manual from NSX Prime.

The link is in the ‘Useful Information’ section of my ‘Technical and Service….Index’ that you can find on the right side of this page.

Please click on the
[ Workshop Service Manuals - ACURA (Link to NSX Prime) zip version is very useful ].

After arriving at the Prime website, scroll down half way and download the
[ 1997 – 2005 Service Manual.zip ].

After extracting the zip file, open any one of the pdf file and at the top of the page, click on the [ Main Menu ] and then [ Brakes (including ABS) ] section.

You will find how to read the error code by clicking on the 19-10c and the reset error code procedure at 19-11c. Example view here;

Diagnostic Trouble Code (DTC)
Indication

’97-99 Models . . . . . . . . . . . 19-48

’00-05 Models . . . . . . . . . . . 19-10c

DTC Clearing

(’00-05 Models) . . . . . . . . . 19-11c

You can also find the pin out of the big black/orange connector at the upgraded ABS modulator on Page 19-6c.


On your SoS upgrade loom, inside the cabin, you should find 2 x single terminal connector.

As I have never seen the actual loom, it is going to be the guess work but one of them should be labelled as DLC (Data Link Connector) and the other one as SCS.

If SoS bought the cable from Japan, then the cable colour for DLC is very likely to be Yellow and SCS as Blue.

Please double check this using the multimeter to check the continuity between the big black/orange connector and these two single terminal after looking at the manual page 19-6c.

DLC is pin#10 and SCS is pin#13 of the black/orange connector.

DLC is for the Honda PGM Tester used at the Honda garage so you can ignore it.

Before turning the IG sw into ON position, you must connect the SCS single terminal on the SoS ABS upgrade loom to the GND level in order to read the error code.

Please do not confuse yourself with the description in the manual 19-10c on using the BLUE SCS terminal at the passenger foot well.

This is for the factory fitted latest ABS system which uses the OEM chassis loom.

We are upgrading the Classic ABS loom so this BLUE 2pin connector won't work for SoS ABS upgrade loom.

Kaz

Hi Kaz,

I just went out to my NSX and checked again, the ABS light turn on when sw the ignition key to on position and it does not turn off. Even after started the engine it still on. It never flash or turn off except i turn off the ignition key.

It looks like it fits into your Q1 description. It might be something to do with the ABS modulator. Or could it be the harness wrong connection?

I just downloaded the 1997-2005 Service manual, i will look into it for the diagnostic. Yes the SOS harness come with 2 single terminal connectors, one in yellow and othe in blue but no labelling.

Thanks again, please let me know what you think. Thanks!

Keno

Hi, Keno.

Just copied all of our comments into the Technical section as it's easier to attach files and so on.
The vBulletin Blog comment is designed for quick chat and not for long technical discussion or attaching lots of files....

Will reply back through the following thread;

http://www.nsxcb.co.uk/showthread.ph...pgrade-Support

Kaz