ABLS vs. traction control vs.VDC

richardminco · 09-15-2004, 09:01 AM

All 4X4 Titans have ABLS (active brake limited slip). According to Nissan ABLS "Directs engine power to the side of the vehicle with the best traction while the abs system is applied to the side of the vehicle with less traction so the tires won't slip as much". So, how is this different than VDC?

Nissan states "Vehicle Dynamic Control (VDC) changes engine power and/or applies the brakes individually as necessary to help stabilize the vehicle in severe turning situations. VDC helps enhance performance in emergency avoidance maneuvers, helps improve vehicle directional stability, and helps provide improved control even on slippery road surfaces." So how is this different than traction control?

Nissan states "The Traction Control System (TCS) operates at all speeds and limits drive-wheel slip (wheel spin) under most conditions, improving driver control of the vehicle in slippery conditions as well as on dry surfaces if the throttle is over-applied."

So it appears the ABLS includes TCS with both engine and braking systems working together when wheels slip. If this is true, some of the other posts which discuss safety and traction would appear to be inaccurate.

What I don't understand is: If you have ABLS can you disengage it as you can the VDC? If you have VDC and disengage it, do you still have traction control (abs working but not engine power)?

I've heard that many VDC owners turn it off in dry conditions. Does that mean that if you hit a gravel patch on a corner you will spin the tires and potentially lose control?

Do owners of 4X4s without VDC ever sense the loss of engine power when wheels slip as described by others with VDC.

Thanks for sharing your knowledge and experiences...

Zardoz · 09-15-2004, 09:06 AM

Most of the trail problems with VDC don't occur if you have some weight in the back.
I leave VDC on and don't even notice it on Death Valley trails but I have 1000lbs of
stuff in the back. I do notice VDC when the bed is empty. About 300lbs of weight
settles down the Titan's rear end just fine.

Zardoz

caltitan · 09-15-2004, 10:05 AM

Quote:

Originally Posted by richardminco

All 4X4 Titans have ABLS (active brake limited slip)...

The electronic stability control system on the Titan is not manufactured by Nissan. It is built by Continental Teves. I don't have the time today, but you might try contacting them to get the answers you're looking for or browse their website. Let us know if you find anything valuable. Here's their web site: http://www.conti-online.com/generato.../index_en.html

IMADOGMAN · 09-15-2004, 10:49 AM

Quote:

Originally Posted by richardminco

All 4X4 Titans have ABLS (active brake limited slip). According to Nissan ABLS "Directs engine power to the side of the vehicle with the best traction while the abs system is applied to the side of the vehicle with less traction so the tires won't slip as much". So, how is this different than VDC?

Nissan states "Vehicle Dynamic Control (VDC) changes engine power and/or applies the brakes individually as necessary to help stabilize the vehicle in severe turning situations. VDC helps enhance performance in emergency avoidance maneuvers, helps improve vehicle directional stability, and helps provide improved control even on slippery road surfaces." So how is this different than traction control?

Nissan states "The Traction Control System (TCS) operates at all speeds and limits drive-wheel slip (wheel spin) under most conditions, improving driver control of the vehicle in slippery conditions as well as on dry surfaces if the throttle is over-applied."

So it appears the ABLS includes TCS with both engine and braking systems working together when wheels slip. If this is true, some of the other posts which discuss safety and traction would appear to be inaccurate.

What I don't understand is: If you have ABLS can you disengage it as you can the VDC? If you have VDC and disengage it, do you still have traction control (abs working but not engine power)?

I've heard that many VDC owners turn it off in dry conditions. Does that mean that if you hit a gravel patch on a corner you will spin the tires and potentially lose control?

Do owners of 4X4s without VDC ever sense the loss of engine power when wheels slip as described by others with VDC.

Thanks for sharing your knowledge and experiences...

Richard,

ABLS helps with FORWARD (and probably reverse)
traction by limiting wheel spin using the braking system only, as I described it to you in my PM.

VDC uses engine power to limit wheel spin. VDC uses engine power and braking to correct for vehicle dynamics (whenever the vehicles programmed parameters for handling are not responding to driver inputs). ABLS does not perform these functions.

You CAN NOT disengage ABLS.

Don't confuse ABS (anti-lock brakes) with ABLS (Active Brake Limited Slip)

richardminco · 09-15-2004, 11:32 AM

IMADOGMAN - According to Nissan you are incorrect. However, I don't know if Nissan even understands this. According to Nissan, ABLS includes traction control and it includes using engine power to limit wheel spin. They read some internal manual to me over the phone where they said ABLS "directs engine power"... Now I guess you could interpret this to mean they direct the power by applying the brakes to the other wheels... but that seems rather redundant. Again, what you are saying makes more sense than what they say.

I still can't understand why you would make air bags and VDC mutually exclusive in 4X4s. I guess I'm too stubborn to believe in total stupidity. I'm looking at Tundra's today. Not what I really want, but then again I can get VDC and air bags together on a 4X4...

Orange Crush · 09-15-2004, 11:56 AM

Traction Control System (TCS)

•TCS is standard on Pathfinder Armada and optional on Titan.

•The traction control system reduces torque to the drive wheels by altering injector pulse and controlling the Electronic Throttle Control (ETC) motor. If necessary, the brakes are also pulsed via the ABS control unit and hydraulic unit to reduce slipping.

–For injector pulse and ETC functions, the ECM receives wheel slip information from the ABS control unit through the Controller Area Network (CAN) bus.

TCS operates at all speeds and limits drive-wheel slip (wheel spin) under most conditions, improving driver control of the vehicle in slippery conditions as well as on dry surfaces if throttle is over-applied.

Vehicle Dynamic Control (VDC)with TCS and ABS

•The VDC system is standard on Pathfinder Armada. The system integrates ABS and TCS with additional cornering controls.

•The VDC control functions (integrated into the ABS control unit) monitor the input from steering wheel angle, vehicle speed, wheel speed, G-force and yaw rate.

•When vehicle stability is affected by road conditions or the need to make an emergency maneuver, the system helps to maintain optimum speed at each wheel.

•The system controls engine output by reducing fuel and throttle opening,and provides individual braking control for each wheel to reduce or prevent skidding.

VDC changes engine power and/or applies the brakes individually as necessary to help stabilize the vehicle in severe turning situations. VDC helps enhance performance in emergency avoidance maneuvers, helps improve vehicle directional stability, and helps provide improved control even on slippery road surfaces.

Note:VDC not available with locking rear differential.

Active Brake Limited Slip (ABLS)

When ABS wheel-speed sensors detect a loss of traction in one or more wheels, braking force is applied to that wheel to help slow it down. This redirects power to the wheels with better traction.

IMADOGMAN · 09-15-2004, 12:36 PM

Quote:

Originally Posted by richardminco

IMADOGMAN - According to Nissan you are incorrect. However, I don't know if Nissan even understands this. According to Nissan, ABLS includes traction control and it includes using engine power to limit wheel spin. They read some internal manual to me over the phone where they said ABLS "directs engine power"... Now I guess you could interpret this to mean they direct the power by applying the brakes to the other wheels... but that seems rather redundant. Again, what you are saying makes more sense than what they say.

I still can't understand why you would make air bags and VDC mutually exclusive in 4X4s. I guess I'm too stubborn to believe in total stupidity. I'm looking at Tundra's today. Not what I really want, but then again I can get VDC and air bags together on a 4X4...

ABLS does direct engine power...to the wheel that has the most traction. It does nothing for Vehicle stability by itself. It may enhance vehicle stability...if it is part of the VDC system, but only by use of the braking system to control wheel spin to regain traction. ABLS, without any of the other systems does exactly what I told you it would do...that is to redirect torque to the wheel that has most traction, by braking the wheel that is spinning. The name is very descriptive. "Active Brake Limited Slip"
I don't see where anything that I have said disagrees with Nissan...only your interpretation...
I have never seen the TCS "Traction Control System" acronym in any Titan literature...only VDC "Vehicle Dynamic Control".
These may be the same thing with a different name....I don't know.

Slappy · 09-15-2004, 02:03 PM

richardminco,
The VSC(Toyota's stability control system) and side air bags on the Tundra DC are very difficult if not impossible options to find. I've tried and have not found any even though Toyota says that they are options, I don't think they have built any with those options for 2005 yet. Maybe later in the year.