ABS trouble-shooting (SOS '01+)?

[R13]

Background:

Installed SOS '01+ ABS update on my '92. The ABS has worked flawlessly for over a year in all conditions. Let me first say that it's highly unlikely my problem lies with the update:

The problem:

-I got the car back from having the axles rebuilt (amongst other things) and it was throwing an ABS light (no TCS light).

-The car was also hesitating a bit so intuition, and indeed the manual, suggests it's a rear wheel speed sensor.

One had been recently replaced, the other was older than dirt. I replaced the old one. I drove the car around for ~15 minutes: no light. Got an alignment, now I've got a light again....

The question:

If I go to the stealership, will the ABS diagnostic tool work on my car given the frankenstein system? Or is there some other method I can use to pinpoint WTH is going on?

 

[nsx_2k]

R13,

On the upgraded system, there is a two pin pigtail connector. You should be able to short the two pins and the ABS light will blink out the codes. Not sure if you recall, but the pigtail was attached to the loom that was threaded into the cabin.

I've used that jumper on the pigtail and the newer service manual to aid in diagnosing issues with the upgraded system.

 

[pgilliam1]

Did you pull any error codes from the ECU?

 

[R13]

Ah, ok, no. I brain-farted on that one. I just pulled out the instructions from SOS and the two loose wires are the equivalent of the check connector for the new system. Pulling codes shortly.

 

[R13]

Ok, I couldn't get any codes to pull. I jumpered the leads, turned the ignition on (no start) and got a solid light, no blinking.

I then turned the car on, drove it ~10 minutes, parked it and tried agian. Same result. Only when I re-started the car I had no ABS idiot-light for another 10 minutes.

I really hate sporadic issues. Mainly because that means it's probably electrical.

 

[pgilliam1]

I don't think it's a coincidence that the problem started after you had the work done on your car. The shop could have damaged the WSS you had already replaced. Have you tried pulling codes from the ECU test connector? Is the ABS working properly? Does the TCS work as it should?

 

[R13]

I don't think it's a coincidence that the problem started after you had the work done on your car. The shop could have damaged the WSS you had already replaced. Have you tried pulling codes from the ECU test connector? Is the ABS working properly? Does the TCS work as it should?

The WSS I had replaced before having work done was in the front. All of said work was performed on the back of the car. One rear WSS was replaced during the course of the work, and the other was replaced immediately afterwards (by me due to the ABS light coming on as above).

I haven't had the opportunity to properly test the ABS or TCS (although it's raining today, so that's a possibility). Hopefully I can run a few more tests or worst case, spend some quality time with a multi-meter over the weekend.

 

[R13]

Update:

Still chasing this....:frown:

However, what I've determined so far:

• When the ABS light is off, the ABS really does work.
• When the ABS light is on, it really does NOT work.
• When the light is on, the car will buck under part throttle at times unless I also turn off the TCS.
• It seems to be at least somewhat temperature/usage dependent.
  • The failure condition seems to happen when:
    • I track/autocross/take a trip up the dragon (so even moderate spirited driving will trigger it, not necessarily flat-out track use)
    • I sit with the brakes on for a minute or two after a long highway run (stop light at an exit ramp for instance)

I've pulled the airbox out and the trunk carpet so I can follow the wiring around from both of the rear WSSs to the main harness. There are no breaks that I can see, or any duplication of janky wiring practices I've found elsewhere on the car. The main harness isn't pinched or stretched anywhere that I can tell.

I'm going to pick up a better multi-meter this afternoon (a digital one) because I don't think the analog thing from the '70s that I've been using is quite right. Then I plan to Ohm all of the WSSs to make sure I didn't end up with a lemon somewhere, and that the one that hasn't been recently replaced hasn't gotten flaky on me (although it's in the front, and wouldn't be in the TSC loop that I'm aware of).

Is there anything else that could cause this type of shenanigans? I know the Main Relay, and some other fail-safe relays are in this loop. Anyone have experience with one of those causing similar symptoms?

 

[Larry Bastanza]

Ok, I couldn't get any codes to pull. I jumpered the leads, turned the ignition on (no start) and got a solid light, no blinking.

This sounds like the "jumpered" connection is not good, since the light is on, just like it is when the jumper is missing. I have had this issue many times with the original jump conector for ODBI.

I would be checking the pulse wheels on both rear axle shafts(outer CV Joint housings), to see if any teeth were damaged. These teeth are what pulse the WSS's to deliver speed info to the system.

HTH,
LarryB

 

[R13]

This sounds like the "jumpered" connection is not good, since the light is on, just like it is when the jumper is missing. I have had this issue many times with the original jump conector for ODBI.

I would be checking the pulse wheels on both rear axle shafts(outer CV Joint housings), to see if any teeth were damaged. These teeth are what pulse the WSS's to deliver speed info to the system.

HTH,
LarryB

I tried a few different ways to make that connection, but never got any results. Started with a bent paper clip that I use for that purpose quite a bit and moved to a pretty thick wire section with gator clips on either end. You make a good point that the light should at least go out though....I'll drop by radio shack and see if I can find an actual connector for that type of lead so there's no question.

Also, once the car's been off for ~15 minutes, the fault goes away on it's own, so if I don't immediately jump out of the car and try to pull the codes, then they may clear on their own.....otherwise this would have been over with a while ago.

I thought about the pulse wheels, but figured it would do it all of the time if it was an issue with a tooth/teeth. Maybe not the case?

I got around to thinking about relays because I know as they start to go bad they can start to "stick" when they get hot.

 

[Hagasan]

Just for info, you don't connect the two pigtails together. One is the SCS signal and the other the DLC signal.

You don't use the standard SCS blue plug in the footwell for the new ABS. What you need to do is ground the new SCS wire. Can't remember the colour but it goes to pin 13 on the ABS black/orange plug. Forget the DLC wire

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.

You upgraded the Classic ABS loom so this BLUE 2pin connector won't work for SoS ABS upgrade loom

Hope that helps, just made up my own harness a few weeks ago when installing my ABS....

 

[R13]

Just for info, you don't connect the two pigtails together. One is the SCS signal and the other the DLC signal.

You don't use the standard SCS blue plug in the footwell for the new ABS. What you need to do is ground the new SCS wire. Can't remember the colour but it goes to pin 13 on the ABS black/orange plug. Forget the DLC wire

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.

You upgraded the Classic ABS loom so this BLUE 2pin connector won't work for SoS ABS upgrade loom

Hope that helps, just made up my own harness a few weeks ago when installing my ABS....

You're correct. That's what I've been doing since I realized that. There are two loose wires on the SOS harness, one is the SCS and the other goes to ground from what I can tell. It's just top to question whether I've actually been able to make that connection.

 

[Hagasan]

You're correct. That's what I've been doing since I realized that. There are two loose wires on the SOS harness, one is the SCS and the other goes to ground from what I can tell. It's just top to question whether I've actually been able to make that connection.

No that's not correct.

You need to ground the SCS wire on the SoS loom, the one that goes off to pin 13 on the ABS plug. I don't know the SoS wire colour, it's blue on OEM wiring.

The other wire, forget it, leave it alone, don't ground it. It's the DLC wire which plugs into a Honda tester.

So ground the new SCS wire, don't touch the original blue SCS plug in the footwell, then turn ignition on and you should get the codes then as per the manual....

 

[R13]

Ok. Picture is worth 1000 words:

Here are all of the ABS-Related connectors in the passenger foot-well of my car:

My understanding was, with the updated system and S0S harness, I just connect the two SOS leads to each other (i.e. Connect #2 to #3 in the picture). I know that #1 will not pull codes for the new system because it used to be connected to the old ABS computer which is no longer in the car.

Am I wrong? Should I just be grounding one of the SOS leads and leaving the other alone?

Exhibit A)

 

[Hagasan]

Ok. Picture is worth 1000 words:

Here are all of the ABS-Related connectors in the passenger foot-well of my car:

My understanding was, with the updated system and S0S harness, I just connect the two SOS leads to each other (i.e. Connect #2 to #3 in the picture). I know that #1 will not pull codes for the new system because it used to be connected to the old ABS computer which is no longer in the car.

Am I wrong? Should I just be grounding one of the SOS leads and leaving the other alone?

Exhibit A)

Just either 2 or 3.

If you have a meter then check which of the two colours goes back to the pin 13 on the ABS plug or pop the cap off the plug and check which colour is on 13. Once you confirmed which one of the two wires it is then ground that wire...

From what I've heard of the SoS harness it can be a little weak at the two white plug connectors. I've heard of the odd wire breaking off so it might be worth check there too....

 

[R13]

Ok......so.

One point of housekeeping:

I just spoke with Chris@SOS on the phone, and to pull codes with their kit, you simply connect the two loose ends to each other (i.e. plug #2 into #3 from the pictures above). This was what I had been doing and what was described in post#2, but confusion was introduced when no codes pulled.

This may end up being a side-note as well, but all of the WSSs Ohm out in-spec.

I haven't tried pulling codes again yet, because I may have found the problem (and a relay wouldn't necessarily generate a specific code):

Every time I've looked at that relay box, I thought that blob had been there as a ghetto fix for the slightly loose lid to the sub-relay-box.....not so much it seems. Just one more reminder that the PO had this thing serviced at a gas station in NJ.

 

[nsx_2k]

R13, this may sound strange, but I recommend that you look at the large white connectors that are fed INTO the cabin and plug into the existing orange wiring harness. Some of those solder points can fail or come loose. I personally had this happen to me. It is a grade A pain to resolve, but one tip would be to *gently* pull on each individual wire to see if it pops off. Don't pull hard, just gently. They are covered with shrink tubing so it is difficult to tell if they have failed by merely looking at the wire.

Since you are having bizarre issues, I would check the harness first. I realize that there are a lot of wires, but it may just be your problem.

 

[R13]

R13, this may sound strange, but I recommend that you look at the large white connectors that are fed INTO the cabin and plug into the existing orange wiring harness. Some of those solder points can fail or come loose. I personally had this happen to me. It is a grade A pain to resolve, but one tip would be to *gently* pull on each individual wire to see if it pops off. Don't pull hard, just gently. They are covered with shrink tubing so it is difficult to tell if they have failed by merely looking at the wire.

Since you are having bizarre issues, I would check the harness first. I realize that there are a lot of wires, but it may just be your problem.

If replacing the relay doesn't cure it, I'll probably start looking closer at this. Fingers crossed for the $35 fix for now.

 

[Hagasan]

Ok......so.

One point of housekeeping:

I just spoke with Chris@SOS on the phone, and to pull codes with their kit, you simply connect the two loose ends to each other (i.e. plug #2 into #3 from the pictures above). This was what I had been doing and what was described in post#2, but confusion was introduced when no codes pulled.

This may end up being a side-note as well, but all of the WSSs Ohm out in-spec.

I haven't tried pulling codes again yet, because I may have found the problem (and a relay wouldn't necessarily generate a specific code):

Every time I've looked at that relay box, I thought that blob had been there as a ghetto fix for the slightly loose lid to the sub-relay-box.....not so much it seems. Just one more reminder that the PO had this thing serviced at a gas station in NJ.

I'm sorry to say here but Chris is wrong on this one, I'll explain why refering back to your picture showing the wiring in the footwell.


Your original blue SCS plug has a blue wire and a green/white. If you check the shop manual you will see that blue wire comes from the ABS as SCS. The green/white wire goes to ground via ECM (SG1) at ground point G101.
What that means then is that when you wanted to read codes on the old system you connected your SCS to Ground by putting a short in the blue plug.

Now you have the later wiring your SCS wire is (I don't have an SoS harness but worked it out for you) the blue/red one going to the bullet connector. So, in order to configure you ABS to display trouble codes (DTC) you need to ground this blue/red wire with a piece of wire. You do this before you turn the ignition on.

I even checked the OEM wiring for the later ABS and sure enough, the blue wire from the ABS on Pin 13 goes to the blue SCS connector then on a Black/Brown wire to Ground at G101.

So if you are not following that procedure then your going off on a tangent. If nothing works with the above procedure then it's probably as I said previously and NSX_2K recently, that your white plug connector wires have a break somewhere. A friend of mine who bought the SoS harness had a broken wire and I've read of a few others too.

The Yellow/Blue wire on the SoS harness is for plugging into the Honda tester....

when you said throwing an ABS light. Are you saying that the light comes on at start up and never goes off once fired up but staionary or that it goesout then comes on again?


Good luck & Hope it helps eventually

 

[R13]

when you said throwing an ABS light. Are you saying that the light comes on at start up and never goes off once fired up but staionary or that it goesout then comes on again?


Good luck & Hope it helps eventually

Typically, it's come on while driving, or shortly after a hot start (i.e. hasn't been off for long). Then it stays on until the car has an opportunity to stay off and cool down for ~15-30min, and then doesn't come back on at start-up.

I'm tempted to leave a WSSs unplugged after I swap out the relay and confirm which method for pulling codes actually works, lol.

 

[Hagasan]

Does your ABS actually work if you stamp on the brake pedal hard? If it does then it may just be the harness relay playing up as thats used to activate the ABS light on the dash...

I think you'll find my method works ;-)

I read your earlier post again and it would appear you are just going to have to methodically bell out your wiring to check for breaks in wires. If not a wiring fault or WSS's then are Larry suggested, maybe the teeth were damaged when the drive shafts were refitted....Is the distance between the WSS and the gear correct? Can't remember if it's adjustable or not?

Guess there's only so much you can advise on the net without being hands on....

 

[Larry Bastanza]

First of all, Hagasan, great info. I hope Chris will chime in to confirm, or explain if his harness is possibly different.

After re-reading all of this, I think you need to check the grounding of the system. I had heard to two instances where the ground was not that great and causes unpredictable results. The only thing that makes this hard is it appears this started after your header install. With that said, make sure you check the engine grounds as well.

Regards,
LarryB

 

[R13]

First of all, Hagasan, great info. I hope Chris will chime in to confirm, or explain if his harness is possibly different.

After re-reading all of this, I think you need to check the grounding of the system. I had heard to two instances where the ground was not that great and causes unpredictable results. The only thing that makes this hard is it appears this started after your header install. With that said, make sure you check the engine grounds as well.

Regards,
LarryB

I actually did check the grounding to at least the main points in the ALB loop after reading a couple of threads about brake light problems. I even went so far as to add a second ground wire to a different point on G401, but that didn't seem to help.

 

[etang789]

Another trouble shoot thread
http://www.nsxcb.co.uk/showthread.php?9286-ABS-Upgrade-Support/

 

[R13]

Update:

I replaced the busted relay with a not-busted one. The problem disappeared again until today. However this time both the ALB and TCS lights came on and I was able to pull codes. Hopefully this will lead to progress.

A) Hagasan was correct. Grounding the Blue/Red wire yielded codes.

B) I pulled code 44 from the TCS and code 15 (one long "on" pulse, followed by 5 quick pulses) from the ALB system. Both of these point to the right rear Wheel Speed Sensor. Error 15 in particular indicates (according to the manual) an "open/short to body ground/short to power".

Now I just have to figure out where to look first. I know the WSS-to-Harness lead is fine, , so it seems likely it's somewhere in the trunk harness. Any common failure or pinch points back there?

Oh, and Merry Christmas everyone