How to Check ABS and auto transmission functioning

[Panther]

Please let me have the tips on how to check proper functioning of auto transmission and ABS brakes when testing a used car
What indicators or symptoms point towards malfunction or possible weaknesses.

Thx

[hash4u]

take the car to like 35-40 km/hr and brake hard.u will feel the tyre lock and unlock. means abs is working.drive the car around.gear change should be smooth means transmission is alright

[wheeels1]

@ panther

I will try give the information about checking your auto transmission.

1) The important thing is to ask the owner if he has EVER changed the auto transmission Fluid A.T.F ? (usually in the land of pure people never tend to bother with changing the ATF and this is disasterous for the Auto tranny!

2) Start the engine let it come to the normal operating temperature. Turn off the engine and remove the ATF dipstick wipe it, reinsert it and again remove to check the level of ATF as well as the COLOR. The level should be with in the marked levels and It should NOT be black or
very dark brown.

3) Now for the driving part. Start the engine press the brake paddle and then shift the car into "D" or "R". You
should feel that the car wants to move instantaneously with in a second. This is good sign, if the car doesn't show interest to move for quite a few seconds then the trany is questionable!

4) Now lets take it for a test drive. Move the lever to D4/D and Slowly increase the speed from 0 and as you increase the speed you will feel that the car is smoothly changing the gears. Take it to about 80km/h so that all four gears are checked. There should be no slippage of the gears during this test.

5)How to Check D3 or 3:
Now reduce your speed to lets say 60km/hr and shift the lever to D3 should immediately feel the car Downshifting to 3rd gear(this is a good sign). And now your transmission is locked in 3 gear. Now if your speed has decreased lets say to 30-40km/hr press the throttle and increase your speed, this time you will feel that when you cross the limit of 3rd gear the car will not shift to 4th because you have it in D3 or 3 position. this is a good sign.

5)How to check D2, 2 or S:
Drive the vehicle at lets say 40km/hr and move the lever to 2 or S, with out pressing the brakes you should
immediately feel the car Downshifting to 2Nd gear(this is a good sign). And now your transmission is locked in
2ND gear. Now if your speed has decreased lets say to 20-30km/hr press the throttle and increase your speed,
this time you will feel that when you cross the limit of 2ND gear the car will not shift to 3RD because you have
it in D2/2/S MODE Position. this is a good sign.

if any where the car's Auto trany response is not immediate then the tranny is questionable.

And remember to always change the ATF every 30-40000 km.

Hope this helps,

Thanks

[sami_voodoo]

Also check if the transmission kicks down when you depress the accelerator to the floor. 4th to 3rd or 3rd to 2nd. I've driven a bunch of cars that were a bit reluctant to kick down.

Cheers!
Sami

[Panther]

hash4u, sami and wheels1,
Thx a lot for the input. It was really very educative and helpful.
I took test drive of a car that had ABS but its indicator was not working and the dealer told me that " SAB KUCH THEEK HAY BUS KOI FUSE URR GHIA HO GHA". I dont think fuse can blow up without any fault.

regards

PS: Wheels1 special thx for a detailed reply.

[zianadeem1]

jus chk if the transmisson is not replaced..or else accelerate the car and when the gear shift's..focus that time that it does not take a sudden jerk

and for ABS-
just push full brakes.ul hear a sound..nuthing else can i say..i dun think so that in used cars ABS sumtimes not functioning perfect.its perfect al the time

[ailiahaider]

@Wheels, excellent explanation bhai...

For ABS, just as everybody else said, push the break pedal hard at 50-60km speed. The pedal should feel like hammering as the antilock releases the brake pads once its locked and releases it again. This happens very quickly and several times within a second (the release and grab process). Its like a burst going off from a G3 lol

I have driven some cars with problem in ABS system and the thing that i have noticed is that the intervals becomes longer then it should be...

[wheeels1]

@panther,

you are welcome.

As the other honorable members have given you the insight about checking of ABS, I will just try to put my 2 cents in:

1) Turn on the ignition switch to 2nd position, meaning when all the lights come on (without starting the vehicle).

2) You will note apart from other indicators that the ABS indicator will turn on.

3)Now start the vehicle, all the other lights go out, The ABS light may go off the last, meaning 0.5-1 second after the other(this is normal and perfectly OK)

4)However after this interval, it should turn off completely and should not come on again! If it comes on again or is taking like 1 minute to turn off then there may be problem with the sensors or any other thing in ABS.

5) Now drive the car and in increase the speed so that you feel that when you apply sudden brakes the regular cars without ABS will screech. Now apply sudden hard brake and DoNot release the brake paddle. You will feel the brake paddle pulsating or shuddering (this is NORMAL) and you DONOT take your foot off the paddle in a real emergency situation.

6)You will not hear the screeches made by the ABS equipped car because it doesn't allow the wheels to lockup.

7) On a wet road you will not even have to increase the speed of the vehicle too much for the ABS to kick in!

8) Kindly when you perform the ABS testing do it on an EMPTY stretch of road to avoid any accidents. Also donot push the vehicle very hard without any ACTUAL emergency for testing the brakes or you will over heat the brakes of the potential car you are buying. Just do a normal test!

NOTE: There is misconception in our drivers that ABS equipped car will do wonders as far as the stopping distance is concerned. Mark the words :"The braking distance of an ABS equipped car and that of a NON ABS car is EQUAL, SO DONOT HAVE THE MISCONCEPTION THAT THE ABS EQUIPPED CAR WILL STOP IN A SHORTER DISTANCE. The only ADVANTAGE which you have with an ABS equipped car is that you can Maneuver the vehicle (meaning that you can turn the steering wheel slightly to avoid the obstacle in front of you and come back to your original lane without losing control of the vehicle)". All this will be done when simultaneously you have pressed"hard the brake paddle without letting it go when you feel the shudder. If you release the brake paddle during the shuddering than you will do worse than a regular car as far as braking is concerned!

Hope this helps!

[hammie21]

@wheeels1
bro m ur fan yaar wat a detailed explaination for auto trans. and ABS ....gr8 knowledge.. it helped me a lot ... cuz m buyin a auto and ABS car..thankx man...(R)

[bilal_khan]

wow @ wheels1...

[its_me]

@wheeels1
great explanation of auto trans and ABS both...
one thing that i wanted to clear... i think in some cars auto trans doesnot down shift even if u move the lever to D3 or D2 position unless a suitable speed is reached...
e.g. u going at 100km/h in 4th gear... u move the lever to D3... auto trans will not down shift the gear unless speed come aounrd 70km/h (suitable for 3rd gear)

please correct me if i am wrong...

[wheeels1]

@its_me

You have touched upon another topic…

If you see the earlier post the advisable speeds to check the D3 and D2 are considerably lower ie 40-60 KM/hr and this is as a safety net to Avoid transmission damage!

At high speed as you have posted ie 100 km/hr or Higher speed than 100km/hr, there may be cars (ALTHOUGH HAVE NO EXPERIENCE WITH SUCH CARS) which donot downshift to 3rd gear from 4th until appropriate lower speed is reached but that may their Safety net to avoid transmission damage. Meaning if a person suddenly downshifts a car from D4 to D3/D2 at lets suppose 140-180 km/hr you will cause Transmission Damage! But the same is true for manual transmission also!

Similarly you would not want to shift from D (drive) to R (reverse) if the car is moving forward otherwise you are bound to cause transmission damage. The car needs to come to a complete stop from forward motion to be shifted to R.

Now lets consider another example (hypothetical). A person is going fast eg 140-180 km/hr and suddenly he comes to know that the All the braking systems on the vehicle have failed. The option he has now would be to shift the lever from D4 to D3/D2 to Try to slow down the vehicle. Now if the vehicle is Not equipped with the safety mechanism which you mentioned earlier the vehicle will downshift and slow down causing Severe Damage to the Tranny, however saving the emergency situation. On the other hand if the vehicle is equipped with the safety mechanism as you mentioned earlier (vehicle not immediately downshifting till the appropriate lower speed) than what will be the way of slowing down the vehicle?

NOTE: These are my personal views and NOT expert opinion, so I don’t take any resposbility for any incident or explanation or accident. Moreover I have not seen or experienced the down shifting of Auto Tranny from very high speeds as mentioned by @ its_me.

Thanks

[its_me]

u r rite... may be someone having experience abt it can guide us

[adam86]

Very interesting

[Panther]

@Wheels1
Today I test drove a car and noticed that on turning the ignition switch to position 2 , ABS light was the first to go off as compared to other lights like that of airbags etc . Is that normal?

[wheeels1]

@panther,

It seems to be perfectly Normal in your case.

1)When you turn on the switch the ABS and Check engine light comes ON and then goes out in an instant.

2)Then when you start the car, the ABS light may come ON again for a second and then turns OFF.

3)After this time the ABS light should not come ON, if it does then there is a Problem!

Hope this helps!

[Panther]

@wheels1

Thx. You have always been very helpful.

[suzukialtomehran]

Nice Info guys