[sidindica]

anshuman, it seems like a case of major manufacturing defect, especially multiple sensors failure and premature electricals failure .

I advise you NOT TO drive the car and keep it as it is parked. Escalate the issue to Mahindra, because Mahindra does enjoy a decent reputation of customer satisfaction, you can call their helpline-with you hamesha and see if something can be done.

Its a lemon which has not had passed QC tests. Hope this is just a rare case. And please, do not indulge in manufacturer bashing and keep favouring toyotas. You know how they are suffering in a massive scale in US and Europe and of course in India, too with respect to fortuner brakes.

Scorpios have known to be generally reliable, but this kind of problems is really serious and can easily erode customer confidence in a brand.
Mahindra, please do something about it urgently.

And anshuman, keep all the records of all the work carried out in the workshop properly filed including the bill and the job card. It comes in handy during warrenty claims.

[Viper21]

This is absolutely sad. lucky no one was hurt. On the topic of the clutch, My colleague was stuck on some highway with his clutch out of order and Mahindra is like "Yeah this happens with some Scorpios"

[Viju]

Originally Posted by Sutripta

"Complete" failure on a dual circuit "failsafe" system? I think we are missing something here.

Multichannel system. Sensor and actuator per channel. And I'm sure the controllers are designed to fail in "safe mode". If not, it is extremely poor design, and would lead to huge product liability costs.

Have to agree with Sutripta here.

Complete failure on a diagonal circuit is very improbable. Even in case of a vacuum booster / pump failure, the base brakes will not fail completely.

Electronic braking systems always have failsafe built into them. If any sensor fails, ABS warning lamp will light up and the system will be shut down (and the normal brakes will continue to function). This is not specific to OEMs (say Tata, Mahindra or Toyota) and is a legal requirement globally (if not in India) and is therefore inbuilt in all electronic braking systems.

Since you say that the light had been switching ON and OFF, it would most probably be something to do with the electronics. Best idea would be to escalate the matter as soon as possible.

[raj_5004]

+1 to sidindica. scorpios are known to be reliable but with getsurya's recent experience of wheel popping out from a running scorpio & now this, their reputation is going for a toss.

[jkdas]

Originally Posted by raj_5004

+1 to sidindica. scorpios are known to be reliable but with getsurya's recent experience of wheel popping out from a running scorpio & now this, their reputation is going for a toss.

raj; it might be coz of a bad a.s.s. team and not coz of bad manufacturing. You can have a good vehicle but if you put in bad fuel and run it, who is to blame ?

[raj_5004]

yes jk, getsurya's experience was because of a bad A.S.S, but how can a bad A.S.S cause a brake failure?

[amitk26]

Originally Posted by SS-Traveller

I agree.

The electronics governing the ABS would also be common. If the booster was the culprit, disconnecting the ABS system would not have got the brakes working normally again - which it now does.

Rat damage to ABS-related wiring?

Well if ABS wiring is damaged at the max ABS should not be actuated but that can not result in break failure , It looks more like leakage in break liner or damaged washer /seal

In case it was RAT damage I am sure A.S.S would have highlighted it multiple times to anshuman

[ImmortalZ]

It takes quite a few catastrophic failures for complete loss of braking. Without the ABS sensors, the system shuts down. But normal braking still works. If you lose the brake booster, you still get unassisted braking. If you lose a brake circuit, you still get braking on the other set of wheels. Loss of hydraulic pressure will set off the ABS warning light. As will the loss of ABS sensors.

Also, brake lines are susceptible to rat bites. They are only reinforced rubber lines. Even steel braided lines aren't rat proof. But these things are usually tucked into the frame work, so they wouldn't be exposed. But with M&M who knows.

I have a close friend whose Scorpio has had non functioning ABS straight from the showroom floor. No warning lights. However, push the pedal too hard and all hell breaks lose (pun intended). You cannot panic brake and expect to be facing the same way when the smoke clears. Or even the right side up. The driver side power window works when the moon phase is right. Front right suspension is seriously wrong somewhere. Local A.S.S can't diagnose the issue.

The car is now two years old and has run only 5000 odd KM.

[Sutripta]

Originally Posted by Viju

Have to agree with Sutripta here.

Complete failure on a diagonal circuit is very improbable. Even in case of a vacuum booster / pump failure, the base brakes will not fail completely.

Originally Posted by ImmortalZ

If you lose the brake booster, you still get unassisted braking.

My money would be on the booster rather than the ABS. One will still have unassisted braking without the booster. But in practice, it is barely better than the emergency (hand) brake. To the person driving this 2 ton projectile, one moment with proper brakes, the next with unassisted brakes, it will feel like complete failure. (I would suggest this experiment, but it is simply too dangerous on open roads, deserted or not. Take your Scorpio to say 40 Kmph. Switch off engine. Lightly pump brakes a couple of times. Now try stopping the vehicle.)

A clarification to my earlier post: "Fail in safe mode" is not the same as "failsafe".

@Anshuman
Without a full diagnosis (one which stands up to reason, corroborated by physical evidence) and corrective action, the fault is likely to recur. So please exercise due diligence!

Also try and get the A.S.S. to give in writing that the ABS unit is at fault, and then forward a copy to the ABS manufacturer. I am not saying this in the spirit of "lets stick it to the manufacturers" but in the hope that the problem will be diagnosed properly. I have very little faith in Mahindra's A.S.S.s technical competence. Just trying sincerely, and with a smile is sometimes not good enough.

I must add once again, IMHO, it is not the ABS unit. However, if it is, if the ABS unit can fail this way, it should be highlighted in every possible forum till the manufacturer takes action. It is simply too important, too dangerous.

Regards
Sutripta


Regards
Sutripta

[SS-Traveller]

Originally Posted by amitk26

Well if ABS wiring is damaged at the max ABS should not be actuated but that can not result in break failure , It looks more like leakage in break liner or damaged washer /seal

In case it was RAT damage I am sure A.S.S would have highlighted it multiple times to anshuman

Originally Posted by ImmortalZ

Without the ABS sensors, the system shuts down. But normal braking still works.

An ABS wiring short-circuit rather than a circuit break? Where the ABS sensors refuse to let the hydraulic circuit activate?

Originally Posted by Sutripta

...the ABS unit. However, if it is, if the ABS unit can fail this way, it should be highlighted in every possible forum till the manufacturer takes action. It is simply too important, too dangerous.

That's right. This is certainly an extremely confusing dilemma, but equally important that the diagnosis be proper.

[amitk26]

Originally Posted by SS-Traveller

An ABS wiring short-circuit rather than a circuit break? Where the ABS sensors refuse to let the hydraulic circuit activate?

That's right. This is certainly an extremely confusing dilemma, but equally important that the diagnosis be proper.

Well if it is short from the logic point of view it is a constant slip detected, ABS module should apply a pulsating breaking at more then 40 times in a min, rather then not actuating the hydraulic circuit at all.

So then it is a faulty ABS logic and not just an short/open ABS sensor circuit.

So under these circumstances I think then M&M ABS is a dangerous proposition to have.

[getsurya]

sutripta,


well put! My take is the brake master cylinder has a problem.

To all,I will actually suggest what Sutripta mentioned about the braking without ABS- please try it and this will let us know how to be ready for any such eventualities.

[HappyWheels]

If the ABS is at fault, it will either be pulsating all the time (due to wrong signals being received) or do nothing; either way the brakes should work. Looks like a brake failure here.

And since we all have this hydraulic assisted braking, the moment it fails, we are at loss, since it then becomes difficult (very difficult), but not impossible, to brake. We are just not used to it and will not be able to judge properly, to stamp on the brake, during a normal drive.

This is directly in reference to what Sutripta has mentioned.

The best case in such an eventuality is to use the hand brakes, with the risk of a skid, rather than the muscle work out.

To all: Please do not try out what Sutripta has mentioned unless you are in a very safe environment. No "empty" road will do.

And before we nail the coffin on the ABS, I think this is just a one-off case. We have so many people with Scorpio's with ABS here and none have had this experience. So, it is just a case of a bad piece (although this is of no console to the affected person!!!)

[getsurya]

Guys,

I agree with Happy wheels on trying what Sutripta said only ON empty roads.

I recently finished my 35k servicing done. M&M was against me for synthetic engine oil, so I settled in for M&M CROWN which was supposed to be better than the current one(maximobile or something!). I do find the engine noise less and the ride smoother than earlier. I also opted for newer transmission oil & gear oils.

Any body have any observations with CROWN or is it a placebo for me!!

[condor]

Originally Posted by getsurya

Any body have any observations with CROWN or is it a placebo for me!!

It is possible because the oil is still fresh. Check again after you have driven a bit - maybe another 500+ km.