So, I bought my 96 about two months ago now (42K mi, 5-speed, CTSC)... started having the EPS failure not long after I got it. Usually, when I'm pulling out of my driveway and parking spot at work, turning at slow speeds. I've been doing the fuse pull/reset but that is obviously temporary. Then I cleaned the battery terminals and added another ground per some forum posts. Then I tried to look up codes with OBDII reader, and it shows no codes. I thought maybe I needed to do the paperclip thing to find the codes, but i don't have the bright blue connector that the wiki page says to use. Any other way to find out which code I'm having? I'm obviously trying to avoid replacing my whole steering rack, so are there any other things I should try or places to check for electronic faults first?
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I have the EPS problem, but no codes are coming up. Please help!
- Thread starter laclipz
- Start date
The EPS problem? I think there is more than one EPS problem. You need to specify the nature of your EPS failure. Are you getting: loss of power assist with an EPS warning light, loss of power assist with no EPS warning light , just the EPS warning light coming on while still having power assist? Every time you start up the car does it start out with power assist and then quit or are you only getting assist after clearing the error codes and the assist disappears after an error code appears?
The OBDII monitoring system is only used for the emission / engine control functions and some auto transmission functions which are controlled by the ECU. The TCS, ABS, EPS and SRS are separate and independent of the ECU and OBDII system and the only way to access the error codes for those systems is through the service check connector and the 'count the flashing light sequence procedure' which means that you need to do the 'paper clip thing'. Every first gen NSX is built with a service check connector and its there unless somebody removed it which would be strange. The service check connector is not that easy to get at, especially if it has never been accessed. It is normally tucked up on the right side of the passenger foot well (no where near the OBDII port) under the right side of the glove box. You may need to remove the cover under the glove box in the foot well and go probing with your fingers in the area on the right side. There are one or two large wiring harnesses that run in that area and the service check connector may have got caught behind the harness during vehicle assembly so that it is not easily visible.
The OBDII monitoring system is only used for the emission / engine control functions and some auto transmission functions which are controlled by the ECU. The TCS, ABS, EPS and SRS are separate and independent of the ECU and OBDII system and the only way to access the error codes for those systems is through the service check connector and the 'count the flashing light sequence procedure' which means that you need to do the 'paper clip thing'. Every first gen NSX is built with a service check connector and its there unless somebody removed it which would be strange. The service check connector is not that easy to get at, especially if it has never been accessed. It is normally tucked up on the right side of the passenger foot well (no where near the OBDII port) under the right side of the glove box. You may need to remove the cover under the glove box in the foot well and go probing with your fingers in the area on the right side. There are one or two large wiring harnesses that run in that area and the service check connector may have got caught behind the harness during vehicle assembly so that it is not easily visible.
Sorry for lack of specifity. Yes, I have the issue where power assist shuts off and the light comes on. Light has never come on while power assist is still working. And yes, the light stays on and power assist doesn't work until I pull the fuse and restart the car. But then it will come on as soon as I make a sharp slow turn, and stay on until I pull the fuse again.
I looked at all photos of where the connector is under the glovebox and couldn't find mine. I was upside down laying there looking up underneath for it. I will remove the cover and see if I can find it there; hopefully like you said it is caught behind another harness, etc. Thanks for the quick response.
I looked at all photos of where the connector is under the glovebox and couldn't find mine. I was upside down laying there looking up underneath for it. I will remove the cover and see if I can find it there; hopefully like you said it is caught behind another harness, etc. Thanks for the quick response.
Have a look at this photo
https://www.nsxprime.com/wiki/Trouble_Codes
As noted, the SCC may have also fallen down behind the carpet in the passenger foot well which may require pulling the top of the carpet out to find it. I only found the SCC on my 2000 when I was installing the keyless entry unit and my fuzzy recollection is that it was kind of squeezed in amongst a bunch of stuff farther to the right than in the photo in the Wiki. I definitely would never have seen it if I had just looked into the foot well area with everything in place.
Depending on what codes you eventually find, you may want to check out Kaz's NSX blog. There are issues with some of the relays in the power unit failing and he goes over replacement of those relays. The EPS control unit also probably suffers from electrolytic capacitor failure. I think there were also some FET failures on the H bridge; but, it has been so long since I looked at his posts covering the failures I can't be sure. Not likely that you have a FET failure because that would result in no power assist under any conditions - even after a reset.
https://www.nsxprime.com/wiki/Trouble_Codes
As noted, the SCC may have also fallen down behind the carpet in the passenger foot well which may require pulling the top of the carpet out to find it. I only found the SCC on my 2000 when I was installing the keyless entry unit and my fuzzy recollection is that it was kind of squeezed in amongst a bunch of stuff farther to the right than in the photo in the Wiki. I definitely would never have seen it if I had just looked into the foot well area with everything in place.
Depending on what codes you eventually find, you may want to check out Kaz's NSX blog. There are issues with some of the relays in the power unit failing and he goes over replacement of those relays. The EPS control unit also probably suffers from electrolytic capacitor failure. I think there were also some FET failures on the H bridge; but, it has been so long since I looked at his posts covering the failures I can't be sure. Not likely that you have a FET failure because that would result in no power assist under any conditions - even after a reset.
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Yeah, I took the carpet up just like that picture, but couldn't find it. I'll take the glovebox cover off this weekend and hopefully find it.
I did look at Kaz's blog... very informative and much of it beyond my electrical knowledge. But hopefully, I get the code(s) this weekend and will post what I learn. Thanks again for all the help. This is a great forum.
There is also this light bathroom reading;
http://www.nsxprime.com/forum/showt...ild-Part-1-of-3?highlight=eps+repair+valhalla
http://www.nsxprime.com/forum/showt...ild-Part-1-of-3?highlight=eps+repair+valhalla
I went out to my car this am and had a look in the passenger foot well to refresh my memory of how things are arranged. When you remove the cover under the glove box, there is a metal bracket with a rectangular hole in it which the pin on the front of the glove box cover fits into (you can just see the lower part of that bracket when the cover is in place). On my car (model year 2000) the SCC was stuffed up into the area just to the right and slightly above the bracket - gives you a place to start looking.
It also appears that I left the SCC stuffed up there safely out of harms way because when I looked this morning the SCC is no where to be seen with the cover in place. I hope I don't have to make use of it.
It also appears that I left the SCC stuffed up there safely out of harms way because when I looked this morning the SCC is no where to be seen with the cover in place. I hope I don't have to make use of it.
Oh yeah, I had a fun scare reading that.
Soooo... I finally found the blue connector after removing the glovebox cover. It was stashed waaaay up into the dash. I got the two long and two short codes. So I guess I need to send the EPS power amp to get rebuilt? That’s BrianK right?
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Perhaps; but, not looking good. If you review the service manual, you will see that there are some other things that can cause code 22. Unfortunately, hard to check without the special test equipment; but, might be worth reviewing first before you rip things apart.
I don't know whether Brian K does EPS modules. Might be worth a PM to him to confirm first. You could also try d1 guy
http://www.nsxprime.com/nsx-prime-vendor-list/nsx-eps-repair/
I don't know whether Brian K does EPS modules. Might be worth a PM to him to confirm first. You could also try d1 guy
http://www.nsxprime.com/nsx-prime-vendor-list/nsx-eps-repair/
Talked to Brian... sending him my EPS module. Went driving today without it, other than parking and slow sharp turns, the car drives really well without power steering.
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Sent from my iPhone using Tapatalk
I might be having a similar problem with my EPS. I've owned my NSX for about three months. I am new to this car and I've probably only driven it about a dozen times since getting it. Everything has been working great, but today, the red EPS light went on in my 1995. Here is what happened:
Drove it in the morning - no problem. Then as I was pulling out later in the day, I realized that the car had stalled. Strange since it has never stalled before. I figured maybe I didn't turn the key all the way or something. So I restarted and everything seemed to start OK, so I moved on. But I noticed that the steering was hard to turn. I figured that it's something I am still getting used to since even with EPS, it's harder to turn than any of my other vehicles. When about two minutes into the drive, I noticed the red EPS light on.
So I brought it back and left it for a bit. Later, I tried starting it again in hopes that the light is gone. Still there. But this time, I also noticed that the battery gauge was blipping between 14V (normal) to 12V or slightly below. Either battery is dying or something is pulling a lot of current. I shut the engine off and tried to start it. It stalled. The way it is stalling is different than anything I had experience with any of my other cars. When I turn the key, the engine seems to catch, the tach moves up to 2k for a split second and is back at 0. It's as if the engine started and is immediately shut off. There is no strain to start, starter trying to crack over and over. It just catches and then is off. This is what must have happened when it first stalled earlier today which I thought was user error. I tried three times to start the car and it would not.
I have a trickle charger attached to my battery (previous owner installed it). So I connected that to an outlet and the car started. So I am thinking that all the stalling was due to the battery - although the way it starts and immediately stalls seemed strange. Is this the way NSX's stall when battery is low?
The EPS light is still on and power steering hasn't worked since that light showed up earlier today. PS is disabled and the red EPS light comes on when I start the engine and stays there.
I'm wondering if the low battery caused the EPS to shut itself off. I read that there is a false safe system that shut off EPS if there is an issue. I'm charging the battery and will try to restart the car later tonight or tomorrow. Hopefully, the stalling is gone with the battery charged. But not sure if EPS will reset itself once the conditions are OK. Or is this something Acura or some mechanic can only reset. Seems like laclipz unplugged the fuse (I am assuming the 50A fuse in front of car) and plug back in to reset. Is this safe to do. If so, I can try to reset this way. Maybe with the reset and a charged battery, things will be back to normal... Can only hope.
Let me know if anyone has experienced issues with the EPS. Especially due to low battery.
Thanks.
Drove it in the morning - no problem. Then as I was pulling out later in the day, I realized that the car had stalled. Strange since it has never stalled before. I figured maybe I didn't turn the key all the way or something. So I restarted and everything seemed to start OK, so I moved on. But I noticed that the steering was hard to turn. I figured that it's something I am still getting used to since even with EPS, it's harder to turn than any of my other vehicles. When about two minutes into the drive, I noticed the red EPS light on.
So I brought it back and left it for a bit. Later, I tried starting it again in hopes that the light is gone. Still there. But this time, I also noticed that the battery gauge was blipping between 14V (normal) to 12V or slightly below. Either battery is dying or something is pulling a lot of current. I shut the engine off and tried to start it. It stalled. The way it is stalling is different than anything I had experience with any of my other cars. When I turn the key, the engine seems to catch, the tach moves up to 2k for a split second and is back at 0. It's as if the engine started and is immediately shut off. There is no strain to start, starter trying to crack over and over. It just catches and then is off. This is what must have happened when it first stalled earlier today which I thought was user error. I tried three times to start the car and it would not.
I have a trickle charger attached to my battery (previous owner installed it). So I connected that to an outlet and the car started. So I am thinking that all the stalling was due to the battery - although the way it starts and immediately stalls seemed strange. Is this the way NSX's stall when battery is low?
The EPS light is still on and power steering hasn't worked since that light showed up earlier today. PS is disabled and the red EPS light comes on when I start the engine and stays there.
I'm wondering if the low battery caused the EPS to shut itself off. I read that there is a false safe system that shut off EPS if there is an issue. I'm charging the battery and will try to restart the car later tonight or tomorrow. Hopefully, the stalling is gone with the battery charged. But not sure if EPS will reset itself once the conditions are OK. Or is this something Acura or some mechanic can only reset. Seems like laclipz unplugged the fuse (I am assuming the 50A fuse in front of car) and plug back in to reset. Is this safe to do. If so, I can try to reset this way. Maybe with the reset and a charged battery, things will be back to normal... Can only hope.
Let me know if anyone has experienced issues with the EPS. Especially due to low battery.
Thanks.
Looks like my previous question either got lost or is stuck being moderated. It was a long post describing what happened to my car. My follow-up post seems to be there though.
Anyway, the reason why I am asking about the fuse pull is that I am also having EPS issues. It started to happen right after the engine failed to start. It looks like my battery was low and when I was able to start it again, the red EPS light came on and I can't get it off and my power steering does not work. Just wondering if anyone had this experience with the system locking out EPS due to low battery power. I am wondering if I charge (or change) my battery, if this issue will go away. Or even with a new battery, whether I need to reset the EPS (by pulling fuse). The two issues might not be related, but they happened to me at the same time. I am hoping a simple battery exchange will solve my EPS problem. We will see. I am currently charging my battery through a trickle-charger. Will try to buy new battery tomorrow. But in the meanwhile, looking to see if anyone had this kind of problem before with EPS shutting down with low battery power.
Anyway, the reason why I am asking about the fuse pull is that I am also having EPS issues. It started to happen right after the engine failed to start. It looks like my battery was low and when I was able to start it again, the red EPS light came on and I can't get it off and my power steering does not work. Just wondering if anyone had this experience with the system locking out EPS due to low battery power. I am wondering if I charge (or change) my battery, if this issue will go away. Or even with a new battery, whether I need to reset the EPS (by pulling fuse). The two issues might not be related, but they happened to me at the same time. I am hoping a simple battery exchange will solve my EPS problem. We will see. I am currently charging my battery through a trickle-charger. Will try to buy new battery tomorrow. But in the meanwhile, looking to see if anyone had this kind of problem before with EPS shutting down with low battery power.
Hey Rufus, I did the fuse thing when car was on and off, but only worked for me when the car was off. I would get power steering back temporarily only. Eventually, or even sometimes right away, it would go away.
I got my EPS unit back from BrianK this past weekend -- no EPS lights and no issues with the power steering the last couple days of driving. Another satisfied customer! Thanks NSXPrime.
I got my EPS unit back from BrianK this past weekend -- no EPS lights and no issues with the power steering the last couple days of driving. Another satisfied customer! Thanks NSXPrime.
Hi laclipz,
Great news on your EPS. I tried the fuse "trick" and it worked for me. EPS light is gone and power steering is back. For now, I am hoping that the light initially came on because of my low battery. I will keep my eyes on it to see if the EPS light comes back as it did for you until you repaired the unit.
By the way, when you say that you got your EPS unit back, you are referring to the power steering ECU module?
Great news on your EPS. I tried the fuse "trick" and it worked for me. EPS light is gone and power steering is back. For now, I am hoping that the light initially came on because of my low battery. I will keep my eyes on it to see if the EPS light comes back as it did for you until you repaired the unit.
By the way, when you say that you got your EPS unit back, you are referring to the power steering ECU module?
Yeah, this...
Thanks for the photo. For now, replacing the main battery and resetting the EPS seems to have done the trick. The EPS light originally came on right after the car failed to start due to battery. Since the new battery, the car has not had issues starting and power steering has been operational. Let's hope it stays that way. Thanks for your help.
Well, my EPS light is back. Drove the car for about an hour today, a nice curvy road without any steering issue. But then towards the end of my ride, while on the highway, I noticed the EPS light on. The steering was noticeably heavier as I pulled off the highway and the rest of the way home. I was able to reset the EPS light again as you had suggested before. But it looks like I have a real issue since the light was back, even with a new car battery.
Sounds similar to your issue [MENTION=11893]laclipz[/MENTION]. I might need the EPS ECU repaired. One thing I noticed was that when I got home (with EPS light on), I wanted to see if just restarting the car might make the EPS light go away. When I shut off the engine and restarted, it stalled. It started the second time. EPS light still there. So I shut off the engine, pulled the fuse, reset, and started the engine again and this time, it started the first time. EPS light is gone since I reset it.
I'm not sure if you had stalling/starting issue while you had the EPS issue. The car had never stalled until I had the EPS light issue. Not sure if it's related. Not sure if one is causing the other. Trying to figure this out. Would appreciate anyone to chime in if they have helpful suggestions.
Thanks, all.
Sounds similar to your issue [MENTION=11893]laclipz[/MENTION]. I might need the EPS ECU repaired. One thing I noticed was that when I got home (with EPS light on), I wanted to see if just restarting the car might make the EPS light go away. When I shut off the engine and restarted, it stalled. It started the second time. EPS light still there. So I shut off the engine, pulled the fuse, reset, and started the engine again and this time, it started the first time. EPS light is gone since I reset it.
I'm not sure if you had stalling/starting issue while you had the EPS issue. The car had never stalled until I had the EPS light issue. Not sure if it's related. Not sure if one is causing the other. Trying to figure this out. Would appreciate anyone to chime in if they have helpful suggestions.
Thanks, all.
My car never stalled with this issue, sorry. I would contact BrianK... see what he says. It sounds like you need to fix your module like I did.
Next time the EPS trouble light comes, do not reset the EPS using the clock fuse. Retrieve the error codes stored in the EPS controller (there may be more than one). The error codes may give you an idea as to what is going on. If your EPS continues to work for a period of time after a reset your problem sounds a little different than laclipz's problem.
When you replaced the battery did you check the condition of the battery post clamps and the cables. These can get damaged over time leading to poor electrical connections which can really mess with the EPS operation. Also check the condition of the battery - cable where it bolts to the car body and the grounding of the EPS control module.
When you had the stall condition was it a failure to achieve a successful engine start (perhaps tried to start; but, failed) or did the engine start, run a bit and then quit? If the first condition its likely because the fuel system lost pressure. Always allow the fuel pump to prime and pressurize the fuel rail before starting. The fuel system has a check valve in it to hold pressure when parked; but, as the cars get old the check valve can leak causing pressure loss. This is a fairly common problem as the cars get older and it can be really hit and miss. A leaky injector will do the same. If you had the second condition that is a bigger problem and could be caused by bad electrical connections (and lots of other stuff).
When you replaced the battery did you check the condition of the battery post clamps and the cables. These can get damaged over time leading to poor electrical connections which can really mess with the EPS operation. Also check the condition of the battery - cable where it bolts to the car body and the grounding of the EPS control module.
When you had the stall condition was it a failure to achieve a successful engine start (perhaps tried to start; but, failed) or did the engine start, run a bit and then quit? If the first condition its likely because the fuel system lost pressure. Always allow the fuel pump to prime and pressurize the fuel rail before starting. The fuel system has a check valve in it to hold pressure when parked; but, as the cars get old the check valve can leak causing pressure loss. This is a fairly common problem as the cars get older and it can be really hit and miss. A leaky injector will do the same. If you had the second condition that is a bigger problem and could be caused by bad electrical connections (and lots of other stuff).
Thanks laclipz. It looks like I may need to contact BrianK. But I'll wait until the EPS goes out again and I pull the error code. By the way, where is that module you had to pull out to send to BrianK?
Old Guy, the car dies immediately when stalling. Basically when I start, the engine revs like it's starting, but then the idle is at 0. Basically, it starts for like a 10th of a second - enough to know that it responded to the key turning, but then engine is stalled. Most of the time, it will start the second or third time I try (this was before I changed the battery). One time, it did not start after five tries and I thought maybe it was the battery. So I plugged in my battery tender and then it started. So I assumed it was battery related. But perhaps it's because I gave it time to reset fuel system pressure.
Once I changed out the battery, I had no issues so I assumed both the stalling and EPS was battery related. I drive the car maybe once a week so perhaps I have driven it two or three times since the battery replacement and there have been no issues. But this last time, the EPS light came on about an hour into my drive. And the stall occurred after I got home and I tried to restart the car in an attempt to reset the EPS.
It looks like there may be multiple things happening. The stall and EPS might be unrelated, although I think it has only stalled when EPS light has been on - I think...
I'll get the error code when the EPS light comes on again.
From what I recall, the terminal wires from the battery looked like they were in good condition. There were some build-up on the positive terminal which I cleaned before installing the new battery. But the cables looked good.
Old Guy, the car dies immediately when stalling. Basically when I start, the engine revs like it's starting, but then the idle is at 0. Basically, it starts for like a 10th of a second - enough to know that it responded to the key turning, but then engine is stalled. Most of the time, it will start the second or third time I try (this was before I changed the battery). One time, it did not start after five tries and I thought maybe it was the battery. So I plugged in my battery tender and then it started. So I assumed it was battery related. But perhaps it's because I gave it time to reset fuel system pressure.
Once I changed out the battery, I had no issues so I assumed both the stalling and EPS was battery related. I drive the car maybe once a week so perhaps I have driven it two or three times since the battery replacement and there have been no issues. But this last time, the EPS light came on about an hour into my drive. And the stall occurred after I got home and I tried to restart the car in an attempt to reset the EPS.
It looks like there may be multiple things happening. The stall and EPS might be unrelated, although I think it has only stalled when EPS light has been on - I think...
I'll get the error code when the EPS light comes on again.
From what I recall, the terminal wires from the battery looked like they were in good condition. There were some build-up on the positive terminal which I cleaned before installing the new battery. But the cables looked good.
If you read the rest of this thread, you'll get the directions, links, etc. It's under the passenger footwell. Go here:
http://nsxe-repair.com/eps.html
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The easy check for the condition of the battery post clamps is after you have tightened the clamp nut, see if you can twist the clamp on the post. If you can, then the clamps have been damaged and need to be replaced. If the clamps won't twist on the post, then they are probably OK.
When you go to start the car, don't turn the key from off immediately to crank. Turn it to run, wait a couple of seconds (to let the fuel pump prime) and then turn it to crank to start the engine. If this makes the problem go away, then you have a leaky fuel check valve or a leaky injector which is causing fuel pressure loss when parked. The leaky check valve can be intermittent. My 2000 will do the fail to start or sputter and die thing maybe once a month if I forget to let the fuel pump prime before starting. Fixing the check valve requires dropping the fuel tank to access the fuel pump and if I am going to go through that particular hassle for sure I am putting in a complete new pump.
Given the age of your car, your die after starting could also be the classic ignition switch starting to fail. The engine will start when the key is in the 'crank' position; but, die as soon as the key is released back to the 'run' position. The failure can be intermittent. Sometimes you can fix this by taking the switch apart and cleaning the contacts; however, given the hassle of doing the Removal and reinstallation I think most people would just install a new one. They are not super expensive, particularly if you buy it from Amayama.com or RockAuto.
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