Troubleshoot code...

[Silver Surfer]

3-4 and 5-1.
Engine light and TCS light comes on!
Bugger.

Anybody help?

SS

[Kaz-kzukNA1]

Hi, Silver Surfer.
For 91 NSX, there is no #34 error code for ECL.
Could you confirm the individual code for ECL and TCS warning light?

Regards,
Kaz

[Kaz-kzukNA1]

Also, did you get ECL and TCS at the same time? Or, ECL first followed by the TCS?
When did it happen?
I guess it was fine for a while and suddenly you got the light??
Any specific driving condition?

Any extra info will help us in supporting you.

Regards.
Kaz

[AR]

Bad ground somewhere perhaps?

[Silver Surfer]

The TCS light seem to come on and stay on after SC install....initially thought it was the excessive power causing it. Disappears after restarting car and doesn't come on unless I give it some real hassle like taking a bend with some throttle etc.

The engine light came on after 50 miles of hard driving with Paul (senninha) this am. This reappears when the car restarts pretty much immediately! Didn't happen for the 1st 170 miles since collecting the car. Now it is there all the time and is not resetted by pulling clock fuse!

The TCS blink code is definately 3 long and 4 short followed by 5 long and 1 short.

I wonder whether it is some loose connection as it seem to occur after some spirited driving and may have dislodge a connection or something.

Since the engine light has occcured...the car suddenly loose power on pressing the throttle and the exhaust note clearly drops...the engine still runs but feels like you put it into too higher gear...Like a turbo lag.
I release the throttle and depress the throttle and everything is OK again until I lift off and the same may happen again on trying to accelerate.

SS

[NSXGB]

Similar symptoms for me, turned out to be a wheel sensor.

I had slightly different code though.

[AR]

Remove the rear upper bulkhead trim, remove the passenger side rear bulkhead trim. All clips BTW. Disconnect the TCS. Remove the clock fuse and try it again.

That is what "I" would do in my Neardenthalish way.

Cheers,

AR

[Silver Surfer]

Would the TCS cause the engine light to come on?

SS

[Kaz-kzukNA1]

So. you got 3-4 and 5-1 for the TCS warning light.
What about the error code for the ECL?

Kaz

[NSXGB]

Would the TCS cause the engine light to come on?

SS

Yes, my ECL came on as it went into limp mode, same as yours did.

I believe there is a way of checking the ABS sensors resistance. I would assume that if it's an open circut, it's NFG.

Something to cross off the list if they are all ok.

[Silver Surfer]

How do I get ECL warning code?...Does that flash as well?

SS

[AR]

Do you mean how you retrive them?

I think the ECL is what the Americans call CEL.

Cheers,

AR

[NSXGB]

How do I get ECL warning code?...Does that flash as well?

SS

Yes, ECL and TCS will flash.

EDIT: TCS light and TCS light can flash to indicate fault codes.

[Silver Surfer]

Yes, ECL and TCS will flash.

Jeeps..miss this altogether!!

Will go and check now!! Give me 5!

SS

[AR]

SS why not unplug the TCS and reset the system and see what happens?

[Silver Surfer]

Well...the engine light does not flash! Just stays on with the oil light next to it while the TCS in the top centre blinks away!

Will do AR technique in the morn.
How easy is it to remove the rear upper bulkhead trim + remove the passenger side rear bulkhead trim? Am I going to break any clips etc? Which silver box is the TCS?

SS

[NSXGB]

So which code are you getting from the TCS light? 3-4 or 5-1?

[Silver Surfer]

So which code are you getting from the TCS light? 3-4 or 5-1?

Both. Flashes 3-4 and 5-1 alternately.

SS

[NSXGB]

Check this from Prime:

http://www.nsxprime.com/FAQ/Troubleshooting/tcs.htm

[Silver Surfer]

Thanks Simon,

I keep the possible main relay problem in mind after checking all the wheel sensors.

SS

[Kaz-kzukNA1]

Hi, Silver Surfer.
Probably it’s too late but I hope following information will help you in diagnosing the problem.

First of all, you didn’t mention anything about the ALB2,3 fuse to reset the TCS (and ALB/ABS) controller.
On non-DBW model like yours, removing the ‘Clock’ fuse (7.5A) won’t reset the TCS (and ALB/ABS) failure code. I’m quite sure your mechanic disconnected the battery during the SC installation as it requires different ACG from another model so still both errors were triggered after the installation but this doesn’t mean #3-4 and #5-1 triggered on the same day.
As you have already read the error code, it is best to remove the ALB2,3 fuse to reset the TCS memory bank and carry out another test driving as long as you are clear on what is happening on the engine side.

It is still possible to trigger the wheel speed sensor failure only on TCS controller if you have wiring issue between TCS and ALB/ABS controller or sensor power supply issue but very unlikely to be the case.

By the way, please pay extra attention to ALB/ABS warning light even if you haven’t triggered it this time. Even if you short the SCS blue terminal, it won’t keep repeating the display of error code indefinitely on ALB/ABS case. It times out and no longer shows the error code after a certain period.

All of the wheel speed sensors are first connected to the ALB/ABS controller. Then, the signal is conditioned and the level is changed inside there before passing them to the TCS controller.

Therefore, most of the time, if you have wheel speed sensor failure, it will trigger both the ALB/ABS warning light + the TCS one.

Again, under certain conditions, you can trigger just the TCS warning light for wheel speed sensor failure so please take this into your consideration.


Now the Engine Check Light (ECL).
It seems that you didn’t read the ECU error code before removing the ‘Clock’ (7.5A) fuse unless you have other issues such as wiring and etc.

After removing the Clock fuse, did you test driven the NSX to re-trigger the ECL again?

If not, then you have simply erased the error code and no further error was detected.

Under this condition, if you short the SCS blue terminal, the ECL will stay on continuously without blinking.

From your post, it sounded like you were running at very rich A/F after the ECL came on. This could be failure of O2 sensor, certain sensor failure, sensor connector got loose, etc but again, we need to know the ECU error code.

From what I read from other post on this site, it seems that you have some sort of sub-box to adjust the fuelling for SC application.

While OEM ECU has fail-safe mode maps for certain fuelling/ignition failures, I don’t know whether you have such thing on your sub-box or not for the SC application. Also, I don't know whether it has been tested or not on the dyno using fail-safe mode.

Therefore, if you are going to test drive the NSX again to re-trigger the ECL or if you trigger the ECL in the future on SC engine, please be super gentle as I have no experience running fail safe mode maps on SC engine.


Still, the Comptech parts build quality is very nice even before they were purchased by the current owner. I knew the original members through certain projects.
6705


By the way, as AR suggested, you may want to consider disabling the TCS any way.
As everyone has different driving style, ultimately, you need to make the final decision.

On early models, although the TCS was using the stepping motor, it felt like ON-OFF-ON control and nothing like linear one.
Later, when DBW was introduced, the TCS control was improved but still not for my taste.

As in AR's post, you just need to disconnect the connectors (I think there were three...) from the TCS controller.

6703 6704

I couldn't find the better photo of TCS but your NSX is MT so it should look like the big silver box marked as 'MT' in the above photo.
It's behind the left side seat. Although the photo shows the Left SIDE trim (the one mounted along the door openning panel like arched shape) removed, you don't need to do so for this case.

You will need to remove the rear upper trim (the long horizontal one) and the Left Bottom trim (the square one behind the seat).

First, remove the rear upper trim. Press down gently using both hand holding the top section at about your shoulder width. Then, tilt the top section towards you and lift it upwards. In the photo, you will see three white clips at the top and four L shaped metal bracket at the bottom. Please pay extra attention to the sharp pin close to the Left edge of the trim.
It is so easy to bend it if you try to force removing the trim.
By the way, the pin will be on your right hand side as you will be facing rearwards when removing this trim :).
Then, remove the square bottom trim behind the left side seat below the trim that you just removed. It is held by four clips.

Looking at the TCS controller in its original position, disconnect the three connectors at the left side of the box and secure them to avoic any short.

Disabling the TCS by removing these connectors will not trigger the TCS warning light because the controller itself is no longer connected.

In fact, you will no longer see the 'TCS' yellow light even when you turn the IGN SW to ON position. This was used for the lamp bulb check purpose.

After disconnecting the TCS controller, you will store error code #36 inside the ECU forever as ECU is checking the link to the TCS controller which is no longer in the loop.

You won't see the ECL because of this #36 error code while you are driving.
For this error code, ECU needs to trigger the same failure twice which is not possible as there is no TCS controller connected.

I just wanted to raise this point because if you disable the TCS and try to read the error code on ECU at some point in the future, you need to remember that you will get ECU #36 error code everytime.

P.S.
I have the ECU and TCS controllers that were handed from forumadmin.
I belive these were from your NSX and in working order??
If you haven't changed the spec of the controllers for some reasons, at least, you have the back up boxes.


Regards,
Kaz

[Silver Surfer]

Thanks Kaz for your comprehensive reply as always!
You have covered all possibilities.

I will investigate over the weekend as unfortunately work has just got busier since this am and will take all week to sort out.

SS

[Silver Surfer]

P.S.
I have the ECU and TCS controllers that were handed from forumadmin.
I belive these were from your NSX and in working order??
If you haven't changed the spec of the controllers for some reasons, at least, you have the back up boxes.


Regards,
Kaz

Hi Kaz, Thanks for keeping hold of my original ECU+TCS box. When I first got my car, naive me took it to my local Honda dealer to investigate the cause of the TCS lights constant illumination. They told me it was the ECU and TCS box failure. I bought replacement used boxes for a reasonable sum of money. The change it and the fault remained. It turns out to be a faulty wheel sensor!!! :angry:
I passed them to Kevin initially just in case he needed them. I am sure they are both in good working order and may need them myself in the future. I am happy for you to keep hold of them for me if that is OK.

SS

[Silver Surfer]

I have now Ary'd the car and took out the TCS plugs from the TCS box.
Reset the car by taking out and putting back in the Clock fuse and ALB 2,3 fuse.
With 'paperclip'ing..the engine light flashed 4-2.....Rear bank O2 lambda sensor fault!

I will look into this pesky sensor and see if it needs replacing.
The car with the TCS fully disabled now runs normally! :)

Cheers all for the advice.

SS