Thread: Disengaging Traction Control

hey paul did you swallow the rave manual one night and wake up with all this d2 knowledge?, i'm impressed although also a little confused as alot of what you say goes over my head but really appreciate the insight you give.

re brake controller, no plug under the dash you will need to tap into the brake switch wiring, that got me nervous so i ran a wire back to the brake light at the drivers rear. take the light cluster out and the trailer wiring all connects in this area so you can pick up the blue wire going to the trailer plug.

Re-reading the wabco patent on all-terrian abs it is likely that the modified braking which allows the wheels to lock is only active in low range.

The patent actually has a bit of discussion on how the various abs functions need to be modified to work with a locked centre diff:

Patent US5253931 - Control logic for an anti-lock vehicle brake system - Google Patents

An automatic control logic for an anti-lock protected vehicle braking plants is provided for all-terrain operation. In this case, the standard automatic control logic for road operation is switched, by the driver with an all-terrain switch (13) to a special automatic control logic for all-terrain operation. The special automatic control logic generates time periods, during which a short-term blocking of the automatically controlled wheels (12) is intentionally permitted. The locking time periods have a time duration of about 240 ms. The braking distance of the vehicle in cross-country terrain is shortened while a sufficient cornering force remains based on the all-terrain automatic control logic.

The D2 obviously doesn't have an all-terrain switch but does have hi/lo switch input, which is connected to the SLABS ECU and switches between programs.

New Discovery ETC works under all road or off-road conditions up to a speed of 100 kph (62 mph). It has two control strategies, automatically selected according to the corresponding selection of high or low range on the transfer gearbox. In low range, where an ETC brake intervention is less likely to cause an engine stall, a more forceful approach is taken, with the system being even less ‘tolerant’ of any wheel slip. Inhibiting wheel spin in this rigorous way not only helps traction, but also reduces damage to the ground surface, as well as avoiding vehicle fouling and damage.

Originally Posted by OffTrack

I have a sneaking suspicion the D2a abs might be a better in loose gravel than the earlier revisions. I have the MY04 SLABS ECU fitted to my D2 and I keep trying to invoke the horrific behaviour you guys reckon happens on loose surfaces and I'm just not seeing it. The brakes will consistent behave in a controlled manner, or lock up when on loose/slippery surfaces. The only time it's really bad is when you are straddling two surfaces with different degrees of traction - like one wheel on tarmac and the other in loose gravel on the verge.

D2 traction control will absolutely allow you to lock the wheels on loose surfaces.

I've posted elsewhere the WABCO abs off-road braking strategy. It works in 3 stages, above certain point (40-60kphish from memory) brakes will pulse in the normal "evil abs" fashion. However once the road speed drops below that point, the ABS will cyclicly lock and unlock the to allow gravel build up to help slow the vehicle. Once road speed is below 15kph the wheels will fully lock.

This the spiel on the abs from the LR promotion material. The wabco tech docs cover the operation of the all- terrain in more detail.

All-wheel, Four-channel, All-terrain, Anti-lock Braking System

The d2 had this system before any other 4x4. Jeep is playing follow the leader.

I have to agree with that. Mine is a 2002 april build, first regoed in oct '02,
Still the old headlight shape and it behaves exactly as Offtrack describes in loose gravel. I should know , I have 30kms gravel 1 way to bitumen and 85 kms the other way with lots of stock and skippys to contend with resulting in some emergency stops! Much better on gravel than the other half's CRV As far as I am aware it is still stock in the SLABs department , although the ECU has had the update flash done.
After most of my life driving vehicles without TC I certainly cannot think of 1 situation I have been in yet that I would want it disabled! And this disco is without the CDL, which may make a difference to my thinking if it was fitted but I do not think so.

Cheers
Scott

Locking the CDL on gravel roads makes a big difference.

Does it justify the small extra fuel?

depends on how much fun your having

Originally Posted by Franrick

Hey mate, sorry about the green, looked pretty cool to me but I guess if it can't be read there's not much point in using it.
In relation to the TC. It's not something I'm knocking, I think it's great almost all of the time but you must also be aware that there are a few circumstances in the loose stuff where TC isn't doing you any favours.
I'm new to my D2 and love all the nice little things it has and in coming months hope to learn how to use them to my advantage.'
I'm old school when it comes to 4wd's having bought my first 4wd in 1976. Since then I have always owned a 4wd or two of one brand or the other and they all had their advantages and disadvantages but the one constant was that they nearly all went about what they did in basically the same way.
Skip a generation or so and we now have some really good 4wd's most of which have some great technical advancements that get us further down the track or make life easier in one way or the other.
I also own a D1 that took us to the Cape and back a few months ago towing a camper. As you know, it is quite different from the D2 but we still had an excellent trip in a very capable vehicle. I expect the D2 to be more even capable before to long.
It's not my intention to disengage the TC every time I see a bit of dirt but I certainly want to have the option to override it if I think it is not being my friend.
I have spent the last 36 yrs driving 4wd's without TC. I don't think it will be a disaster if I disengage it from time to time. I might even come to have more faith in it sooner or later.
Kind regards, Rick.

Rick,

TC is a wonderful thing that is usefull 99% of the time - the 1% being on rare occasions in soft sand.

If it were a fad not every manufacturer of fair dinkum 4wdrives would have jumped on the bandwagon - they all have and now offer even better versions of TC on the D2.

Embrace technology and enjoy it - it makes 4wdriving so much more effortless and enjoyable. Next to twin diff locks, TC is the next best option.

Cheers,

Franz

oh yes! CDL locked on the Deefer and those 'cruiser trays dont know whats hit them! or rather whats passed 'em

Hi Yorkie,
That's what I did on my D1 when setting up the Tekonsha on it. It was easier to run 2 wires back from the rear of the car (1 to trailer brakes, 1 to stop light wire) than to go to all the hassles of getting to the switch under the dash. Took the pos to the battery through an auto reset circuit breaker and the neg to a good earth. No probs with the controller with about 5k towing.
Cheers, Rick.

well I have to say having connected my CDL up I have found it combined with TC is a mighty good bit of gear, last week went bush and did a very steep climb with and without CDL, the clear winner was CDL and TC, ive used it on the beach in very soft sand and never has TC interfered with momentum, I just gotta make sure that I turn cdl off before shutting down and turn on after start up as ive been told it can cause electronic issues, I would really like to know a scenario where TC would be a pain, I would have thought sand through not gaining speed but so far that scenario has been proven wrong (on my veh anyway), i am following this thread with interest

cheers

Ken