Hi there!

I recently got a G35 (05, manual) and today i did a little test to see how the back goes off in a U turn without disabling VDC. All fun and good but i noticed the SLIP light, didn't blink (or whatever it does). Basically i didn’t feel the car tried to help me stop spinning the wheels. After that i tried to disable VDC but nothing happens when i push the button.

Did a brake test and ABS seems to work.

I scanned the car for errors with one of those bluetooth devices and nothing.

Just to be clear, i don’t have the common issue with VCD, SLIP, Brake lights lit on the cluster.

Do you guys have any ideea what's going on?

 

When u press the VDC button u should get an indication on your dash.

Does the VDC light on the dash light up when u first turn the key on?
Is your VDC button plugged in?

 

Nope, there’s no indication on the dash and also VDC light does not light up when i turn the key.

The button is plugged in because it’s lit up.

Thx for responding!

 

Hmm. The VDC light on the dash should lit up when u first start the car. U sure its not a burned out bulb?

What u can do is jack up one of your rear wheels. Put some chocks or something in front of the other 3 wheels so the car doesnt move forward. Then start the car and put it in gear and give it a litte bit of throttle. U should feel the car automatically applying brakes to that wheel and the SLIP light should flash.

 

Can’t tell for sure if there’s a burned bulb…or how can i tell without taking the dash apart.

I did another test, the road was wet so i hit a hard 2nd. The wheels start spinning like crazy and no help what so ever from VDC or a blinking SLIP light.

Forgot to mention, if maybe that matters, that i have LSD but i think all manuals have it (if my info is right).

 

Yeah the LSD is probably still able to keep both wheels spinning at the same speed, especially on a wet surface. Thats probably why you don’t get the slip light. I have done rolling burnouts and powerslides in my car on wet pavement and I dont get a slip light either.

But if u really want to test it, try the method I posted. That’ll trigger the slip light for sure….and its quick.

 

Ok, i'll try what you said asap and i'll get back to you.
Meanwhile i had a look at the TC module that's under the glove box too see if any wires were tampered but they look fine.

 

You'll still trigger VDC/SLIP with both rear tires turning because they're spinning faster than the front tires. It will cut most of your throttle.

Look VERY closely at your instrument cluster up close and preferably with a flashlight. Is there black electrical tape covering up the SLIP/VDC light on the cluster itself, this will be behind the clear plastic cover, on the black panel display itself. A previous owner may have cut the entire VDC system and used tape to cover up the light.

 

Thanks for your input! I'll have a close look on cluster too see if there's any tape.
I was wandering, are there any sensors regarding VDC on the pedals? For example my cruise control didn't engaged because the clutch pedal didn't touch the sensor.

 

No, the brake pedal has two switches, one for the brake lights, one for the cruise interrupt. The clutch also has two switches, a cruise interrupt switch, as well as a clutch/starter interrupt that's used to engage the starter circuit.

VDC is it's own separate system, it has 4 wheel speed sensors, gets data from the steering angle sensor via CANBUS, there's a yaw sensor in the center console, a main ABS motor closing relay next to the brake master cylinder, and the ABS valve solenoid block which houses the ABS motor which is attached to the brake booster.

When it detects a difference in direction when comparing the steering angle sensor to the yaw sensor (yaw sensor is a fancy compass) then it triggers VDC. If it detects a difference in wheel speed on any tire it triggers VDC.

When VDC is engaged it sends a signal via CANBUS and the ECM limits engine throttle, the VDC computer then closes the ABS relay which turns on the ABS pump motor to create pressure in the brake hydraulic system without needing the driver to pump the brakes manually, the ABS computer then selectively opens/closes the solenoids on the ABS valve block to apply pressure to specific corners of the vehicle to straighten the car back out depending on wheel speed (it will attempt to clamp a spinning tire) or difference in relation between the steering angle and yaw sensor (it can grab a single corner to swing the car a specific direction towards where the steering wheel is aimed at).

You can hear the ABS / VDC system do a self-check each time you turn the car on, the first time the vehicle reaches 5 mph after it's been started it will close the ABS motor relay for 1 second. It sounds like a "grinding/whirring" sound from the engine bay and if you put your foot on the brake while it's doing the self check you'll feel the pulsation in the brake pedal just like if ABS was engaged. It's easier to hear with the hood opened but if you roll down the window and stick your head out you'll hear it too.

 

Oh yeah śhit…u are right. I forgot that I disable the VDC everytime before I start spinning tires 😂

 

Thank you very much for explanations.
As an update, there is no tape on the cluster, checked it.
I tried to hear the sound of ABS / VDC system do a self-check but can't hear it i'll try harder but it's difficult with the clutch chatter from the simple mass flywheel...
As reminder, i tested the ABS slamming the brakes and it works.

 

Sounds like the system might actually be working. Go buy 3-4 gallons of water at a grocery store, find an empty parking lot, pour the water out under your rear tires, then full throttle the car with the steering wheel turned all the way left or right (basically doing donuts) and see what happens. It should kill your throttle and about 1 second later you'll see the dash lights flash, and if you left-foot brake a little while doing it you should feel the brake pedal buzzing from that ABS motor.

Just to verify when you turn the key to ON, during the initialization/lamp check for the cluster, you do see the SLIP and "skidding tires wavy line thingy" illuminate in the center of your dash yes?

 

Sorry for the late reply, currently i’m out on vacation. I’ll try to do donuts when i get back but regarding the lights on the dash when i turn the key on, no, they do not light up .

I’ll also try to find some specialist (mechanic or electrician) but it is kinda difficult because where i live, in Romania, we don’t have Infiniti dealerships, therefore not a lot of Infiniti’s on the roads. We do have Nissan but when i called one dealership, they told me they don’t do Infiniti's.

I was wandering, can VDC system be disabled from the car’s software? I’m a programmer so in my opinion that can be done, even so it doesn’t throw errors/warning lights. But i don’t really know about cars software other than that they can be tuned 😅

 

Ok I gave you a little wrong info, the G35 doesn't have the "skidding tires wavy line thingy" it's just the SLIP light. If you don't have that light illuminate when you turn the key on it could just be a problem with the instrument cluster. When you do spin the tires it should cause that light to start flashing on the dash as well as the throttle limiter kicking in.

I would definitely try spinning the tire first before digging too deep into it. You could also use a service jack and jack up the rear differential to get the tire off the ground, then accelerate in 1st gear which will also cause the car to trigger VDC. Just be careful if you use that method, don't want you to go accidentally slamming into anything

As for programming the VDC to stay off, I'm not sure about that one, it's possible that maybe some European variants of the car didn't even come with VDC, unlikely, but possible. Does your car have the VDC off button?