ABS & TCS lights coming on....climate control fails to work....voltage issue?

[Meeyatch1]

Hello!

So my 1994 NSX, with 207,399 miles on the odometer, has been having a rather worrisome issue the last 1,000 miles or so. When I start the car, the ABS and TCS lights come on, and the climate control fails to work at all (I mean, it will not even turn on), and the radio won't turn on either. I popped out the clock fuse in the fuse box under the hood, disconnected the battery overnight, and the next day everything worked fine. Then later that day, everything failed again. After a 25 - 35 minute drive, the TCS light went out, and the climate control and radio resumed functioning. I have been told that this could be a voltage issue, but the volt gauge on the dash reads a very normal and high number, the battery passed a load test, and I am running out of ideas. It is to the point now where I do not feel confident driving the car anywhere, and that bothers me. Because I have had this car almost its entire life, and I have always felt comfortable taking it anywhere at any time.

What should I do?

 

[JD Cross]

Mitch, I realize the battery passed a load test but how old is it?

 

[Speedmaster]

Mitch - I am following this thread. I am interested to know the outcome as well because like Jim above, I think this could be battery related (I think this due to things going back to normal after a period of time...to me that usually occurs when the contributing systems have been allowed to run for a time.) So, I suspect battery as well. FWIW, my stereo, after replacing it and the speakers, has to "war-up" before it works properly Weird, I know. Battery works fine, holds a charge, etc. I wonder what/if there is a connection to the battery - I suspect there is.

 

[Meeyatch1]

Mitch, I realize the battery passed a load test but how old is it?

Maybe 3 or 4 years old, maximum.

 

[nsxtasy]

Maybe 3 or 4 years old, maximum.

I'd replace it. Battery life varies. In my MDX, I buy top-of-the-line batteries, and I can't get them to last four years.

The other possibility is the attachment of the battery cables to the terminals on the battery could be intermittent.

Still, I'd replace that battery. It's inexpensive and an easy DIY. I bet if you do that, the problems disappear.

 

[shawn110975]

many customers NSX's have come to my shop with this problem well the ABS and TCS problem, so here is what I do that normally fixes it.

all 4 wheels have a speed sensor if you have ever taken one off you will notice they are a magnet they attract metal chunks and dirt and greese follow with it. I take off all 4 sensors and clean them this normally fixes the problem.

I have even seen some that looks like someone took a hammer to them so beat up not sure how they get this much abuse but I have seen it.

and it will not take long to do all 4 and you will not have to clean them for another 10 years LOL

take off wheel, find the wire leading to the other side of the caliper, remove 2 12 mm bolts let the sensor hang down, I use a wire bristle brush to get it nice and shiny again then wipe it with a degreaser. re-install.
depending on how bad it is I then check the spines inside the hole that this sensor is in.. turn the rotor you will see the million teeth spinning slowly turn the rotor and use a tiny paint brush to brush out all the grease I also squirt some cleaner in there
to help agitate the grease clean every single spline. once you get your hand motion down it very quick.
put sensor back in put tire back on and move on to the next wheel should take about 45 min or less.

since both the ABS and TCS are linked this fixes a number of problems

 

[Briank]

I would be looking at the ignition switch, next time it happens wiggle the key.

 

[M-P]

Check out this thread. I had a similar problem and it ends up I just had a loose fuse in the drivers footwell fuse box.

http://www.nsxprime.com/forum/showt...oming-on-why?p=1528138&viewfull=1#post1528138

 

[Larry Bastanza]

This really sounds like a electrical supply issue. I am not 100% sure off the top of my head which circuits are linked to each pole of the ignition switch, but giving it a wiggle is a good idea. Since the units (CC/Radio) are dead, there is either a loose ground or a flakey supply wire/fuse/switch(ignition) or the like. Frankly the fact it is intermittent makes me lean towards BrianK about the switch. The TCS and ABS lights together would indicate a wheel speed sensor, but I find these are really never intermittent, at least I have not seen or heard of it. BTW, the way it is wired is that the ABS system interfaces with the wheel speed sensors and then sends the signals to the TCS unit. So when both lights come on it is typically a dead ringer for a WSS. But this seems like power is lacking, probably for the ABS unit(it is under the dash near the CC/Radio), TCS is behind the drivers seat IIRC.

My $.02
LarryB

 

[nsxtasy]

What kind of TOTL batteries are you buying? Using my Battery Tender, I have had an Interstate Battery in my NSX for over 9 years, still perfect.....

And I do agree, anything over 4 years as a normal daily-driver vehicle is a gift.

There's a big difference between daily drivers and an NSX, in terms of battery life. Many NSX's are not driven frequently - only on weekends, only on sunny days, only for track events, not in winter, etc - and for this reason many of them are kept on battery chargers, so the battery is fully charged all the time. Whereas daily drivers are susceptible to all the factors that kill batteries - used for short errands (so the alternator doesn't get much chance to recharge the battery), used in the frigid cold of winter, and often have many more electrical systems and safety features. I heard someone state that the new MDX now has 40 different computers!

To answer your question, though, the last couple of batteries I had installed in my MDX were by the dealer (for warranty reasons), using whatever 100-month-warranty battery they carry; the first one I bought lasted 40 months. (The batteries used by the previous owner were replaced after 3, 2, and 2 years.) From now on I plan on replacing it every 36 months as a preventive measure, using Costco/Kirkland batteries made by Johnson Controls, which have a 100-month warranty and with which I've had good experience. In my Integra Type R (a car for which my usage mimics the NSX), the original stock battery lasted five years. I replaced it with a Costco/Kirkland battery. Eight years later it was still starting the car fine, but I replaced it at that point as a preventive measure. In the NSX, my stock battery lasted six years. I replaced it with the predecessor of the Odyssey PC-925T, a smaller-than-stock, lightweight battery. Like the Costco battery in the ITR, eight years later it was still starting the car fine, but I replaced it at that point as a preventive measure.

 

[Larry Bastanza]

There's a big difference between daily drivers and an NSX, in terms of battery life. Many NSX's are not driven frequently - only on weekends, only on sunny days, only for track events, not in winter, etc - and for this reason many of them are kept on battery chargers, so the battery is fully charged all the time. Whereas daily drivers are susceptible to all the factors that kill batteries - used for short errands (so the alternator doesn't get much chance to recharge the battery), used in the frigid cold of winter, and often have many more electrical systems and safety features. I heard someone state that the new MDX now has 40 different computers!

To answer your question, though, the last couple of batteries I had installed in my MDX were by the dealer (for warranty reasons), using whatever 100-month-warranty battery they carry; the first one I bought lasted 40 months. (The batteries used by the previous owner were replaced after 3, 2, and 2 years.) From now on I plan on replacing it every 36 months as a preventive measure, using Costco/Kirkland batteries made by Johnson Controls, which have a 100-month warranty and with which I've had good experience. In my Integra Type R (a car for which my usage mimics the NSX), the original stock battery lasted five years. I replaced it with a Costco/Kirkland battery. Eight years later it was still starting the car fine, but I replaced it at that point as a preventive measure. In the NSX, my stock battery lasted six years. I replaced it with the predecessor of the Odyssey PC-925T, a smaller-than-stock, lightweight battery. Like the Costco battery in the ITR, eight years later it was still starting the car fine, but I replaced it at that point as a preventive measure.

After I reread your comment and saw you actually said "MDX" I got it......

Regards,
LarryB

 

[Old Guy]

I would not rush off and replace your battery, yet. When the engine is running, the battery has very little to do with the operating voltage of the car. That is pretty much determined by the operation of the alternator / regulator. Since you said that the voltage is good when the engine is running, I don't think that is the source of the problem.

The radio and climate control system have at least one common power supply via fuse #33 (7.5A) when the key is in the run position. Its the wh/yel wire that runs to both units. When the engine is running, a problem on that circuit knocks out both items. The problem could be a loose or intermittent connection. If the problem comes and goes, its not the fuse. The radio also gets a second separate supply when the key is in the accessory position. The CCU does not get this supply when the key is in the Acc position. So, next time your radio and CCU quit, stop the car and switch the key to Acc. If the radio starts working again, then you have narrowed the problem down to the fuse #33 circuit.

As far as I can tell, the radio and CCU do not share a common supply with the ABS and TCU control until you get back to the ignition switch. As such, if the problems with the TCS, ABS, radio and CCU always appear and disappear simultaneously, your problem may, as others have noted, be related to an intermittent ignition switch. Given the age of your car, this is a high probability. If you want to replace something on spec, I would spend the money on a new ignition switch rather than a new battery.

As a final note, the ABS and TCS are tied into a separate un switched 12 v supply coming directly off of the battery (called the BAT circuit). The OEM NSX battery cable clamps are prone to stretching / fatigue, particularly if somebody got a little too enthusiastic tightening them. Check your clamps to make sure you cannot twist them on the battery posts. If you can, this could be producing flakey voltage on the BAT circuit which would affect the operation of the ABS and TCU. However, I don't think there is any connection between the BAT circuit and the CCU or the radio.