The ABS discussion thread

[SirAlec]

Originally Posted by Jeroen

That makes more sense. I can switch of the traction control on my cars, but not the ABS. Thanks for the clarification

Jeroen

Nope! traction control does many characteristic change to car one of them is also to control ABS by switching it on and off.

[Jeroen]

Originally Posted by SirAlec

Nope! traction control does many characteristic change to car one of them is also to control ABS by switching it on and off.

Nope, that's way to generic a statement. Most Traction control system are secondary functions of the ABS to start with. Disabling the TC doesn't mean the ABS get switched off. It really depends on which system. The TC uses, amongst others, the same sensors as ABS, but again can use other sensors as well.

The ABS sensors provide input to the ECU. It can easily distinguish between a wheel locking (ABS will kick in) or a wheel spinning up (TC will kick in).

Jeroen

[dass]

I tried searching in this thread, but did not find the answer, or I used the wrong words to search.
Is it possible to fit aftermarket ABS? Has anyone done it, what are the implications? Does this void warranty?

[DerAlte]

Originally Posted by dass

... Is it possible to fit aftermarket ABS? Has anyone done it, what are the implications? Does this void warranty?

Not advisable, nor are there many after-market ABS. They key issue here is *liability* to malfunction. Per se, the ABS (even if jury rigged in the car later) is not going to diminish braking if it fails, but you have to remember the liability arising out of an eventuality (accident due to ABS not acting) is completely yours - not even the add-on ABS manufacturer's!

All ABS manufacturers design an ABS system for a specific car, and fine-tune it after 100's of test runs under different conditions on different surfaces. No one else has the wherewithal to replicate the same.

If your car didn't have an ABS system to start with, AND the model does have another variant with ABS, at a pinch one can mount the ABS system later. This is unlikely to be cheap, as this would entail replacing the wire loom / harness too.

[HillMan]

Guys,

Couldn't help posting this interesting image I found on FB.

[Perakath]

From last month the ABS warning light on my Innova dashboard has begun to intermittently glow rather weakly after a 100 km+ highway run. Flickers on for some time, flickers, then goes off again for several minutes. Happens only after extended high-speed drives; never happens in city driving. The car will be going in for a scheduled service next week. Any idea on possible causes so I can call the SA out on any bull he may spew / parts he may recommend replacing?

If it makes a difference, the first time this happened, the blue 'high beam' light also glowed briefly even when the headlamps were dipped. Which makes me think it's likely to be an electronic issue and not mechanical.

The headlamps have been upgraded to run 100/90W H4 bulbs with the necessary relays and wiring upgrades. The car is 5 years old and has run 90k km.

[sagarpadaki]

Originally Posted by Perakath

From last month the ABS warning light on my Innova dashboard has begun to intermittently glow rather weakly after a 100 km+ highway run. Flickers on for some time, flickers, then goes off again for several minutes. Happens only after extended high-speed drives; never happens in city driving. The car will be going in for a scheduled service next week. Any idea on possible causes so I can call the SA out on any bull he may spew / parts he may recommend replacing?

If it makes a difference, the first time this happened, the blue 'high beam' light also glowed briefly even when the headlamps were dipped. Which makes me think it's likely to be an electronic issue and not mechanical.

The headlamps have been upgraded to run 100/90W H4 bulbs with the necessary relays and wiring upgrades. The car is 5 years old and has run 90k km.

Check if your car battery is at end of its life.

[Perakath]

Thanks but battery was changed last year.

[Rintu]

Flickering or intermittent lighting up of ABS light could be because of faulty speed sensors too. Each of the 4 wheels is equipped with a speed sensor which aids in the ABS operation; failure of anyone of these could trigger the light.

Owners of vehicle with ABS should atleast test it atleast ONCE to get a feel of what to expect when it is activated and how it feels from a driver's point of view. I've heard people refer it to as Automatic Braking System instead of Antilock Brake System.

Knowing how your vehicle behaves under ABS activation will definitely help when you really encounter such situations.
a) ABS systems are speed-sensitive and won't be activated at very low speeds (your vehicle's owner's manual should have that info).
b)Do NOT pump the brakes (ABS does it for you). Instead apply firm pressure on the brakes.
c) The main objective of ABS is to give you directional stability while braking rather than skidding sidways or fishtailing.
d) It doesn't guarantee you a shorter stopping distance. (this is an important point). The stopping distance actually depends a lot on the road condition (in addition to your speed). In snow or gravel, infact it takes LONGER to come to a stop.

[DerAlte]

Originally Posted by Rintu

Flickering or intermittent lighting up of ABS light could be because of faulty speed sensors too. ...

No, if a sensor is at fault, the ABS light will be on - steady - till the fault is corrected and error reset. If the fault persists, the light will be on even if the error is reset. In @perakath's case, it is quite likely a loose contact on the PCB holding the lamp / LED.

Originally Posted by Rintu

... a) ABS systems are speed-sensitive and won't be activated at very low speeds (your vehicle's owner's manual should have that info). ...

Popular misconception. ABS will act if any wheel stops rotating while one or more of the other wheels are rotating. This is NOT speed sensitive - it just looks for the rotational anomaly at wheels. There is a speed threshold, but that is usually 1Kmph or less. It is possible to be crawling in snow at 5Kmph looking for a parking spot - and then having to brake suddenly for whatever reason. ABS prevents an uncontrolled slide even at that speed.

Originally Posted by Rintu

... c) The main objective of ABS is to give you directional stability while braking rather than skidding sidways or fishtailing. ...

Let me paraphrase your statement. The main objective is to retain steering control (control on making the car go where you want it to, not control of the steering wheel). ABS will not make the car directionally stable. The car will skid because of differential directional forces due to the momentum of the car at the time the brakes were applied - steering control allows you get it back on safe track.

Fishtailing is an unrelated concept here. Fishtailing is caused by driver overcompensating for skid and turning the steering wheel alternately to the left and right to regain control.

Originally Posted by Rintu

... d) It doesn't guarantee you a shorter stopping distance. (this is an important point). The stopping distance actually depends a lot on the road condition (in addition to your speed). In snow or gravel, infact it takes LONGER to come to a stop.

Another misconception. While there is no guarantee of stopping distance, ABS does shorten the stopping distance (vis-a-vis locked wheel braking) since it prevents tyre-road contact patch heating, which can further deteriorate the braking conditions (melt snow/ice, trap gas from rubber overheating, etc.).

If you have a switch that can switch ABS off in your car, find an isolated road covered with snow, sand or gravel, and test the braking distance yourself with ABS on and off. Keep other conditions identical in both tests.

[ILTDrive]

Originally Posted by DerAlte

If your car didn't have an ABS system to start with, AND the model does have another variant with ABS, at a pinch one can mount the ABS system later. This is unlikely to be cheap, as this would entail replacing the wire loom / harness too.

I was looking at posting the exact same question,

I have a Dzire VDI, the 2013 model and it doesn't have ABS. However the ZDI one has it and I am pretty sure when the Dzire is face lifted like the Swift was recently the VDI variant itself will have ABS. Now the question is, can I get ABS into my car?

[DerAlte]

Originally Posted by ILTDrive

... I have a Dzire VDI, the 2013 model and it doesn't have ABS. ... Now the question is, can I get ABS into my car?

ABS cannot be retrofitted. The biggest hassle is putting in the harness and piping. This has to be done before any other assembly goes into the car (after chassis etc. welding and painting), as the with-ABS and without-ABS wiring harnesses and brake line piping are different.

[joybhowmik]

Originally Posted by Perakath

From last month the ABS warning light on my Innova dashboard has begun to intermittently glow rather weakly after a 100 km+ highway run.

If it makes a difference, the first time this happened, the blue 'high beam' light also glowed briefly even when the headlamps were dipped. Which makes me think it's likely to be an electronic issue and not mechanical.

The headlamps have been upgraded to run 100/90W H4 bulbs with the necessary relays and wiring upgrades. The car is 5 years old and has run 90k km.

Did you get this fixed?
And what was the fix?

[Rintu]

Originally Posted by DerAlte

No, if a sensor is at fault, the ABS light will be on - steady - till the fault is corrected and error reset. If the fault persists, the light will be on even if the error is reset. In @perakath's case, it is quite likely a loose contact on the PCB holding the lamp / LED.

Popular misconception. ABS will act if any wheel stops rotating while one or more of the other wheels are rotating. This is NOT speed sensitive - it just looks for the rotational anomaly at wheels. There is a speed threshold, but that is usually 1Kmph or less. It is possible to be crawling in snow at 5Kmph looking for a parking spot - and then having to brake suddenly for whatever reason. ABS prevents an uncontrolled slide even at that speed.

Let me paraphrase your statement. The main objective is to retain steering control (control on making the car go where you want it to, not control of the steering wheel). ABS will not make the car directionally stable. The car will skid because of differential directional forces due to the momentum of the car at the time the brakes were applied - steering control allows you get it back on safe track.

Fishtailing is an unrelated concept here. Fishtailing is caused by driver overcompensating for skid and turning the steering wheel alternately to the left and right to regain control.

Another misconception. While there is no guarantee of stopping distance, ABS does shorten the stopping distance (vis-a-vis locked wheel braking) since it prevents tyre-road contact patch heating, which can further deteriorate the braking conditions (melt snow/ice, trap gas from rubber overheating, etc.).

If you have a switch that can switch ABS off in your car, find an isolated road covered with snow, sand or gravel, and test the braking distance yourself with ABS on and off. Keep other conditions identical in both tests.

Sorry, to have caused confusion.

My observations were based on my own experience.
a) Had to replace a front wheel speed sensor after the ABS light was flickering.
b) The ABS system on my Nissan Maxima will NOT be activated below speeds of 6MPH (which would be around 10kmph).
c) I don't think any passenger vehicle come factory equipped with an ABS kill switch. We have compared the stopping distances on Maximas with and without ABS (3 of us have the same car, 2 having ABS) in a variety of road conditions. Results were mixed with respect to stopping distances. I'll put it this way - In snow, it takes longer (than you think) to come to a stop.

I would say, test your car to understand its capabilities and limitations.

And thanks for the corrections, really appreciate it

[Perakath]

Originally Posted by joybhowmik

Did you get this fixed?
And what was the fix?

At the next service Lanson Toyota checked the OBD but found no error codes logged. The problem hasn't recurred since. Guess it was some moisture or loose contact or something that sorted itself out.