[motoquest]

Originally Posted by TheWanderer

- Has anyone faced similar issues?

Similar incident happened with me just around a month ago - rats being the culprits in my case.
They had cut the rubber boot which in time damaged AMT box's oil seal leading to leaking cylinder and result was same - it was not repariable and I was asked whole assembly to be replaced. They estimated around 1 lac to be the part cost and other charges would have shot up the bill upto 1.25 lacs around. I was not willing to put that much money for a car that was under 6 lacs Ex Showroom when I got it, hence I sold the car off with heavy heart.

While sharing my learnings on social media, I got to know few other folks who ran into very similar issue with AMT unit (probably the timeline of AMT is around 5 yrs only)

[TheWanderer]

Originally Posted by TheWanderer

That's so sad

Latest update. No major offers from Tata, money was paid, the car has been "repaired" and appears to be working (as of now). Fingers crossed...

Though it was not a happy ending, I thought the above post would be the last update, but it seems I was wrong!

Before completing a month aftter the assured "complete correction" (the "faulty" AMT actuator assembly replacement) which costed around 1 lakh, the car has started showing the same issue again!!! (Mods, I request you to update the title to "Tata Tiago AMT gearbox issue | Rs 93,000 quoted for repairs by Tata and issue still not resolved after actuator replacement")

Now, the "highly knowledgeable" service centre has found out that "clutch plate damage that resulted in the faulty gear shifting" (and this means that the original issue may not have been an issue with actuator after all!)
If it goes like this, I think next they may ask us to replace the engine!

All through this ordeal, we had tried to get someone from Tata who would actually take ownership of this issue, find the real root cause and provide a permanent solution, but, till now, we have not been able find anyone anywhere in Tata Motor's hierarchy. Any help to get some sort of meaningful response (not like the ones that we have got till now) will be appreciated.

Final parting advice to anyone who is looking to by a car - however good their vehicles may seem, please do not by a Tata car if you want a peaceful ownership experience! Lesson leant the hard way

PS: Tata and their service centres may be happy as of now because they could fool one customer and make him pay for a fault which the company should have owned up, but, I do hope they realize that this has ensured that no one in our family and immediate circle is going to go for a Tata car. I was an admirer of Tata, and in the last few years, had been recommending Tata cars as one of the safe and VFM option. Done! I am no longer going to recommend Tata anymore, and no Tata cars for me too!

Tata Bye Bye

[audioholic]

I couldn't find one thing in this whole story - Can the detailed fault codes during this occurrence be recorded? Has the ASC shared this detail? In the video I can see that the 3rd gear is engaged even without the engine running. The Magnetti marelli would not engage that gear directly without something else prompting it to do. It has a robust diagnostic system and will definitely point out the slightest errors. If there are no errors then the input data is corrupt in the BUS, which might be due to faulty wiring. The AMT actuator is the least probable point of failure. The gearbox itself can develop issues with the synchronizer rings which will prevent shifting to a certain gear. But the AMT only has one usual point of failure - the oil pump. Rest of it is as robust as it can be.

[TheWanderer]

Originally Posted by audioholic

I couldn't find one thing in this whole story - Can the detailed fault codes during this occurrence be recorded

As far as I know, the service centre (or anyone else) has shared detail technical data and a real root cause analysis with my relative. The service centre guys are tight lipped when probed for details.

Doing a thorough technical evaluation and getting to a root cause can happen only if someone takes ownership of the issue and puts some effort. Till now, we have not seen that approach. What we got was standard textbook responses.

[yogiii]

Are the AMT issues more prevalent in Tiago with its 1.2L NA engine or are these equally prone in the 1.2L turbo engine in the Nexon?

[audioholic]

Originally Posted by TheWanderer

As far as I know, the service centre (or anyone else) has shared detail technical data and a real root cause analysis with my relative. The service centre guys are tight lipped when probed for details.
.

Basically the AMT unit will have same software and hardware as the Maruti one except for different calibration and maps. From what I understood of this system, if there is no warning lamp lit, and if the gear moves to some random gear even when the car is stationary, that mostly points out to an error in the vehicle speed sensor data that is being sent to the AMT unit. Of course there is an internal mechanism to detect errors in the VSS signal but it only kicks in when the error occurs continuously beyond a set threshold of time.

I had this issue only once in my Celerio where the car appeared perfectly normal with no warning lights, but from Neutral it would shift to 2nd gear directly even though the car was stationary. There was no DTC stored in the history and nor was there a recurrence of this issue. This issue happened in 2017, when the ODO was 17k and today the car is nearing 70k kms and the issue has never come back. And neither was it possible to trace down the issue.

The only theory I can think of with such an occurrence is that the data that was sent to the AMT prompted it to switch to 2nd gear, mainly the vehicle speed data. Even when the vehicle is moving with the gear in neutral, when we shift to D, the AMT automatically switches to the gear which it feels would be suitable for the current speed.

If this issue can be replicated, ask the ASC to read the live data coming to the AMT. Since its Tata and electronics, I think there is some corruption happening at the input data, which is why the issue still persists even after replacing the actuator, which in the beginning might not have been the culprit at all. Similarly, if the car isnt engaging fifth gear and there is no check light shown in the cluster, that also would point to improper vehicle speed being transmitted to the AMT unit. The AMT itself has robust diagnostics, it will detect improper shifts, unwanted shifts and a truck load of other data and for most of it will throw a check light. But if thats not happening, then there would be some external condition which would be seen by the AMT unit as a normal occurrence.

[jerrindanny]

After dreading about AMT Issues in TATA cars, it has occurred to us.
We own a 2019 January purchased TATA Tiago XZA.
We have not encountered any major issues in the last 4.9 years of ownership, except for one-time Oil Sensor replacement.
On November 27 Monday, we had some personal errands to run. We had a run for about 30 km and we reached the hospital for a checkup. After 2 hours from the hospital, we started the car, once the car passed the gate, the AMT fault warning light came in and we parked the car towards the roadside. We waited for 10 minutes with the engine off and started the car again. The warning light still popped up and the Neutral sign (N) was blinking. On moving the gear lever to A(drive), the car was not engaging to drive. The same was was for Reverse and for manual mode as well.
We contacted our local TATA ASC (Focuz Kozhencherry) and asked for our sales advisor. We advised it may be due to a sensor issue and arranged a pick-up. We insisted on a flatbed truck. Meanwhile, I sent my family back to the house and waited near the car. After about 1.5 Hours, the crane service truck reached and we transported the car to the service center.
A job card was opened and since it was almost past 5 pm they said they would start the next day. The mechanics started to take apart the piece under the gear lever and the part behind the air conditioner. They were checking for any loose wires that must have resulted in the error.
The next day around noon the service advisor called us and informed us that on checking the error codes, there were two errors one with TCU and the other with the gear lever. They took apart the gearbox and informed us they would confirm the next day.
Today they informed us that the fault is with the TCU part and needs to be replaced. The total cost of the TCU part is Rs 28096 excluding the labour charges. It has to be ordered and once replaced the issue would be fixed.

Have any fellow owners encountered a similar issue and what was the solution implemented? I am apprehensive about the replacement as I am worried that the issue will persist even after replacement.