Intermittent CEL & TCS (3-1)

[Vi3tBoy]

Hello Prime,

I got this really randomly. Driving normal all sudden the car shuddered for a sec and TCS light came on. Hmmm weird. A minute later CEL came on. Hmm So I turn the car back towards home to swap cars. Not even 2 mins later the car shudders again and both lights off and car is back to normal. So during the drive home those lights would come on and off (sometimes together sometimes seperately) Mostly the TCS light was on. But when the CEL was on the idle was not normal. Sometimes high sometimes way too low close to dying. I get it home and try pulling the codes.

I could not get the CEL. But I did get the TCS to blink. 3-1 is what I got. From the research I did all I could see is other members speedometer would plummet and all they needed was a new speed sensor. But my speedometer was fine.

Next day I start the car and hmm no lights. So I was thinking hmm maybe tire pressure. I checked all of them and they were just a tad low. So I run it to the gas station and get all the air perfect. While getting air the car shuddered and idled funny again I looked inside and both lights back on. Great whatever I try to finish putting in air and car died. I hopped in after I finish and the car started right back up with no CEL/TCS. On the drive home same thing, intermittent.

I try pulling the cel again still nothing but still get the same 31 code for TCS. I tried resetting the ECU by pulling the fuse and did not change anything.

What else can I look into and have anyone else had this problem?

(My friend that has an NSX and is a honda tech hasn't gotten to look at it yet but over the phone thinks it could also be a misfire of some sort so maybe new plugs, or maybe a bad batch of gas, he's not sure about the TCS light though)

Thank you primates.

 

[bngl3rt]

When I had this, it was because a very important wire had frayed and was shorting out against the intake manifold (ground) under the vibration caused by hard acceleration. This would momentarily kill the entire electrical circuit in the car, and when it came back on the TCS light would be on in protest.

Of course, the fun part was figuring out *which* wire was frayed. There are a lot of wires in the car and it could be anywhere. In my case it was in the engine bay but YMMV

 

[Vi3tBoy]

hmm not exactly what I wanted to hear LOL.

I really hope that's not the case and I have to go thru and trace down all the wires.

 

[ekhonda87]

IIRC, bngl3rt's NSX was supercharged and then had the suprcharger removed prior to him purchasing the car, which is probably where the frayed wire would have come from.

 

[bngl3rt]

IIRC, bngl3rt's NSX was supercharged and then had the suprcharger removed prior to him purchasing the car, which is probably where the frayed wire would have come from.

Correct, though I have heard about this happening on SC cars that did not have the supercharger removed as well. The installation of the CTSC kit requires some wires to run through spots that weren't really intended to have wiring in them long-term...

 

[NSX2398]

I had very similar circumstances last year. TCS light would come on .. followed shortly thereafter by CEL. Pulling the clock fuse would reset but problem would come back quickly. I had the fast idle problem but no low idle. Initially, I was getting a couple of codes but it finally went hard as a 3-1 which the shop manual says is either the TCS module, the ECU, or the wiring between them. I think if you check the posts about people with speed sensor problems, they had TCS and CEL but weren't getting a 3-1. After doing some wiring checks, I replaced the TCS .. but still had the problem so I then replaced the ECU which fixed the problem. In my case, I'm almost certain the problem was related to the fact that I had installed the Prospeed ECU chip and as part of that, they had removed the OEM ECU chip socket and had soldered on a new one. If you read some of the Prospeed RDX injector installs .. which also require replacing the ECU chip and socket .. other people have had funny problems traceable to bad soldering of the socket. If yours hasn't been modded, then unfortunately I think you just going to have to bite the bullet and pick either the TCS or ECU to replace. Unfortunately, Acura won't let you order one in .. try it .. and then return it if it isn't the problem. In retrospect, the fast idle MIGHT have been an indicator that the problem lay in the ECU. YMMV.

 

[Vi3tBoy]

Thank you for the responses everyone. My car is not supercharged or has ever been. The ECU is stock as far as I know.

Looks like my first thing to do would be to trade ECU and TCS module with my friend and see which one could be at fault. See if either or both need to be replaced. And while doing that check for the wiring in between.

Anything else I should look into?

 

[Timeless1]

I had something similar. Look at post 70 & 76 on this link.

http://www.nsxprime.com/forum/showthread.php/152121-Multiple-misfire-codes/page3

Could be early symptoms of Main Relay failure like mine but then again could be something else, but main relay is cheap ($59) fix try that first before throwing $$ around. Next would be ignition switch if you have not already replace it yet also cheap fix. Car died on me many times, replaced ignition switch & was good to go.
GL

 

[Vi3tBoy]

I just replaced the Main relay earlier this summer with a brand new OEM one. That should be good to go.

Is there anyway to test the ignition switch before buying one?

 

[vivanshah]

you could try fixing it as described in this thread:
http://www.nsxprime.com/forum/showthread.php/126038-Bad-ignition-switch-Fix-it!

 

[Timeless1]

Like i said, ignition switch is a cheap fix ($59 also) try that first. You can clean it & get it to work temporarily, but why take a risk & get stranded later. I cleaned mine & it only work for 3weeks then failed again, being under that steering/pedal area is tight as hell, almost broke my back.....

Only way to test is when your car dies, then try turning key to Position III & hold it, if car stays on then that's the culprit.
GL

 

[Vi3tBoy]

But does the ignition switch cause my symptoms? CEL TCS?

 

[Vi3tBoy]

Update:
So I finally had some time to go over the car. My friend that is the Honda tech told me to start with something simple first. With the CEL being so intermittent and the fact that I couldn't pull the code for the CEL at all he said it could just be a random misfire. Lets replace the spark plugs. Did that, and when I was reading thru some older threads one of the things that kept popping up was ECU. He happened to have a Dinan ECU that he knew was in perfect working condition. So apart came the back of the cabin to replace the ecu.

Put everything back together and started up the car. It starts up perfect. Better than before. So I let it idle for 15 mins for the ECU to relearn everything like I've read online. So far so good no lights like before after idling for a bit.

I take it out for a little drive cautiously. Everything better thane expected. The farther I got into the drive my comfort level with the car came back so slowly started pushing the car harder and harder. As of now everything is great. I will continue to update this thread if these problems come back in the future.

Here is my question now. What do I look at in the ECU to know if it is indeed no good?

Thank you Primers.

 

[NSX2398]

Good to hear. As I said earlier, mine was fixed too when I replaced my ECU. As you may know from reading the forum, the NSX suffers from electrolytic capacitor failures in the stereo head unit; stereo amps; CCU; etc so that was my first suspicion. I have personally seen this capacitor leakage before, however after opening up the ECU, I didn't see anything obvious. In fact I don't recall seeing any/many electrolytic capacitors at all. However, if the ECU chip is in a socket (as opposed to soldered to the circuit board), then you have an aftermarket ECU and the socket itself could easily be the problem. However, you'd have to take it to a knowledgable/expert electronics technician capable of re-doing the solder joints. Or you can get a new Acura OEM one for about $850 from a couple of the online Acura dealers. I just noticed in your signature that you have a BB (BaschBoost) NSX .. didn't those originally have some kind of piggyback ECU chip (SplitSecond?). If that's the case, then you may need more than just a stock ECU if you want to keep the boost.

 

[Vi3tBoy]

BB as in Berlina Black

 

[Timeless1]

Good to hear you fixed the issue. Update us on what you find wrong on that ECU.
GL

 

[Vi3tBoy]

ok will do. Not sure when I'll have time to run the ECU to the shop for them to look it over.

I'm not sure what i would be looking for unless it's something blatantly obvious.

 

[NSX2398]

I'm not sure what i would be looking for unless it's something blatantly obvious.

As I said above, the typical electronic problem with NSXs is the failure of electrolytic capacitors. These are small round cylindrical components .. like tiny little metal garbage cans. The failures tend to be either a bulge or a leak of internal materials. I'm attaching a picture of my TCS unit (don't have one of my ECU) and the red arrow is pointing at a bulged one. A normal one is beside it on the right. As I said, I don't recall that the ECU had many/any of these.

 

[Vi3tBoy]

I will try to crack the ECU open tonight when I get home depending what time it is. I will see if I notice and bulges.

 

[NSX2398]

Look for leakage on the circuit board under the cap too .. not just bulges. Hard to describe what leakage looks like but it will likely be light colored (but probably hardened) .. but it should be obvious if it's there because it will be like a blob on the otherwise shiny and flat circuit board surface.