I have a 2003 350Z Automatic w/ 68K miles. About a week ago I was on the freeway, dry day outside, and my SLIP light came on and caused the car to stop accelerating, it was the 1st time this happened so I thought maybe I hit an oily spot in the road. But now I notice it does it about 2-3 per day when I am on the freeway doing about 80mph. It kicks on, and I have to take my foot off the gas to get it to stop. Like I said it happens on dry pavement. I was wondering if this is a sensor going bad, rear differential, or even the tranny. Any ideas? I am hoping it will not be a costly fix.

 

What size tires front and rear?

Your complete profile is also important.

Location:
Columbia SC

What model?

 

defective sensors maybe.

 

It's not likely the trans or diff. The slip condition is determined by the wheel sensors so either the sensor is misreading or one of the wheels rotates slower/faster than expected.

Do you have stock wheels and stock sized tires or aftermarket ones? If aftermarket, what sizes? You could be right on the edge of compatible sized tires and that could occasionally throw off the system.

 

2003 Touring.

I have aftermarket wheels, 20x8 1/2 wheels with 255/35-20 all the way around, and 1 1/2" spacers on the back.

 

The ECU is calibrated to have a larger diameter in the rear. Some have reported issues with using the same size all the way around, others say it works fine, most people just go with taller backs to avoid the issue.

If the backs are wearing faster than the fronts, you might try, is rotating them back to front to get the thicker tread out back.

Chris

 

Agree.

VDC expects to see the rear tires about 10mm taller than the front. To VDC it looks like the RPM of the front tires is greater than the rear. This confuses and activates VDC which is the same as shutting down the car.

So VDC is working perfectly.

 

intresting to know... Upon my initial purchase of aftermarket tires I attempted to find rear tires that matched front tires, with regards to overall diameter. I could not find an exact match, but came as close as possible according to some charts I pulled on the interweb. I wanna say the difference in diameters was about 1/4 inch. Either way, everything seemed to work for me. Original tires were 245/35/19(front 19x8.5) 285/30/19(rear 19x10.5).. After I replace the springs with Tein S-techs I noticed I could drive more agressively before the computer kicked in. Currently I'm running 235/35 and 275/30's. I know it's stretched a bit, but I felt it would be more suitable for asthetics/show application.

 

Thanks everyone, that's great news to hear! I am going to put my stock wheels back on and see if that fixes the problem. I will keep everyone posted on the results.

 

It will definitely fix the problem, I have 20's too and I have this problem. It is our tire size we are running.

 

No, it's not the size of the wheel/tire. It's the relative height of the tires. In particular, the front tires must be "shorter" than the rear ones. The same requirement holds for 17", 18", 19" or 20" wheels.

 

i get this problem too. It has nothing to do with the road conditions. When i put on my track wheels and tires (17x9 with 255/45/17 all around), i get the slip coming on at 65mph on ramp. The tires are stickier so I know its not loosing grip. Also, i only have TCS, not VDC.

 

There ya go - VDC is working as designed. If you don't maintain the stagger of the stock tires, it WILL bite you.

 

yea i know, i was just confirming the same tire height all around. i need to get a switch to permanently shut it off. i forget sometimes when im at the track and tcs will cut power mid corner.

 

I'm glad you guys pointed this info out. It's never too late for me to learn something new.

 

Great info, and very helpful! I am new in the 350Z ownership. Thanks everyone.

 

All I have to say is, if you'd done some more research before buying expensive 20" rims and tires, you'd have known about this issue and what to do about it.

 

Just adding 2 cents of info here. When my rear toe was out because of suspension mods it made the slip light stay on. As soon as I had the alignment done it was gone.

 

is there a way to reflash the ecu or something to recognize new tire sizes so that the system can compensate? i knew my track tires would throw off the sensor but when i'm on them, i don't use my TCS.

 

Check out http://www.kptechnologies.com/

They make a "permanant" VDC/TCS off switch controller.