[amilasokan]

Hello everyone,

I recently purchased a used 2021 Polo GT TSI 1.0 which clocked just over 10k Kms. The car was pretty much unused and have been sitting idle for couple months. The previous owner claims that the battery was recently changed from VW service centre as well.

Now to the problem I have been facing with this car. The upshifts happen only at 3000-3100 RPM driving it with a light foot and D mode. Shifting from D1 to D2 happen at around 2600-2800 RPM but all the remaining gear shifts happen exactly at 3000-3100 RPM. I had it taken to VW service centre for a full inspection and service. I mentioned this to them and they recommended resetting the transmission module which they did and did not solve the issue. I went for a transmission fluid change after that as well. New transmission oil worth around 16k was put into it and the shifting still happens above 3K RPMs.

The weird thing is that, when the car goes in a slight downhill(descending a bridge for example), the shifts happen normally. That is, upshifts happen at 2400-2600 RPM. But driving on a flat surface again causes it to shift at higher RPM. The downshifts are perfectly fine and happen at around 1500 RPMs.

The shifts are butter smooth without any issues and I have put an additional 3000 Kms into the car. The next option VW service centre recommended me was to rebuild the transmission which I said No to. I also had the car taken to a third party premium car service centre and the guy said that the shifts are completely ok. There are no error codes whatsoever.

I also came across a post by a member here for a review of Sunset red polo GT TSI which had the same issue when it was new but was solved after the Run-In Period.

I am attaching 2 videos here which demonstrates the issue. One is on flat surface which is 95% of the time and the other one is going down a bridge(where it shifts normally).

Any suggestions or thoughts would be highly appreciated. Thank you.

Video

Going Downhill - https://drive.google.com/file/d/1qd1...ew?usp=sharing

Regular Roads -
https://drive.google.com/file/d/1Jai...ew?usp=sharing

[pkulkarni.2106]

From the video you posted, the RPM & the vehicle speed seem normal. I am presuming that the TCU gets the vehicle speed data from a sensor (I guess VSS) - so in that case, it'd be worth checking the sensor too.

[Geo_Ipe]

Originally Posted by amilasokan

Now to the problem I have been facing with this car. The upshifts happen only at 3000-3100 RPM driving it with a light foot and D mode. Shifting from D1 to D2 happen at around 2600-2800 RPM but all the remaining gear shifts happen exactly at 3000-3100 RPM.

What kind of fuel efficiency have you been getting over the past 3000 km? Have you compared that with other 1.0 Polos?

[amilasokan]

I have been getting 9-10KMPL mixed.

[Bsilver]

Originally Posted by amilasokan

The shifts are butter smooth without any issues and I have put an additional 3000 Kms into the car.

There is nothing mechanically wrong at least with the transmission, try slotting the torque converter in manual mode, and force up-shifts before 3000 rpm, in two ways:

1. Floor the throttle in manual mode and shift before 3000 rpm.
2. With a light foot, try shifting it before 3000 rpm.

If the above two steps are shifting the gears before 3000 rpm and not denying your command, then there is absolutely no need to build the transmission as their is nothing mechanically wrong with it because it is shifting as per driver input in manual. But it is very hard to pin point a mistake as there are no error codes stored. You can try the above mentioned and revert.

[HillMan]

Could be a sensor issue as well.
The TCU assumes you are driving enthusiastically, sports mode, based on Throttle Position Sensor
or in a stop-go-traffic based on Brake Pedal Position Sensor.

Definitely don't go for rebuild of transmission. The mileage you are getting seems normal if most of your drive is in city.

[amilasokan]

Originally Posted by Bsilver

There is nothing mechanically wrong at least with the transmission, try slotting the torque converter in manual mode, and force up-shifts before 3000 rpm, in two ways:

1. Floor the throttle in manual mode and shift before 3000 rpm.
2. With a light foot, try shifting it before 3000 rpm.

If the above two steps are shifting the gears before 3000 rpm and not denying your command, then there is absolutely no need to build the transmission as their is nothing mechanically wrong with it because it is shifting as per driver input in manual. But it is very hard to pin point a mistake as there are no error codes stored. You can try the above mentioned and revert.

I have tried this and there is no issue when shifting in manual mode.

[amilasokan]

Originally Posted by Bsilver

There is nothing mechanically wrong at least with the transmission, try slotting the torque converter in manual mode, and force up-shifts before 3000 rpm, in two ways:

1. Floor the throttle in manual mode and shift before 3000 rpm.
2. With a light foot, try shifting it before 3000 rpm.

If the above two steps are shifting the gears before 3000 rpm and not denying your command, then there is absolutely no need to build the transmission as their is nothing mechanically wrong with it because it is shifting as per driver input in manual. But it is very hard to pin point a mistake as there are no error codes stored. You can try the above mentioned and revert.

Tried it. No issues shifting in manual mode. Can shift under 3000 RPM in all gears.

[MotoBlip]

Why not try performing a reset yourself? Here's a video that might help.

https://youtu.be/NA4EsBFnfkk?feature=shared

[PearlJam]

Could there be a high rolling resistance issue due to jammed brakes, or under-inflated tyres? In that case, there will not be enough power in higher gears, so the transmission would try to be in lower gears to prevent stalling.

[amilasokan]

Originally Posted by MotoBlip

Why not try performing a reset yourself? Here's a video that might help.

https://Youtu.be/NA4EsBFnfkk?feature=shared

This is applicable only for DSG. Mine has the AQ250 Torque converter.

[amilasokan]

Originally Posted by PearlJam

Could there be a high rolling resistance issue due to jammed brakes, or under-inflated tyres? In that case, there will not be enough power in higher gears, so the transmission would try to be in lower gears to prevent stalling.

This was my thought to. Had this checked a week back and there are no jammed brakes and tyre pressure is correct too.

[audioholic]

Also check the ESP or transmission for any inclination sensor. If they are out of calibration it might cause wrong inclination info to be provided to the transmission hence making it upshift late. Second issue is wheel resistance which the transmission can detect and hence shift late.

[Bsilver]

Originally Posted by amilasokan

Tried it. No issues shifting in manual mode. Can shift under 3000 RPM in all gears.

If you are not experiencing any problem in shifting of the gears in the manual override mode, then there are lesser chances that the internals are bad in the transmission. The transmission in your vehicle has the AISIN 09G model Torque converter. AISINWarner is the OEM supplier for the torque converters in some of the cars in the VW family.

There is a learning mechanism in the TCU in this gearbox which adapts to the driving style of the driver, and any work done to the transmission, the workshop should force re-learn to adjust to the driving habits of the driver. This is the adaptive shifting mechanism which is built in the TCU which cannot be changed unless you force it to re-learn. Since you told that you recently purchased the car, the gearbox has been adapted to the driving style of the previous owner, and also when you did any transmission job, they need to force re-learn via ODIS for the transmission in order to avoid any complications. The best you can do now is, go to a dealer and ask them to force re-learn on the transmission and then drive about 100kms and check whether the problem is persisting or not. Once this is done at the workshop, initially the shifts might be erratic and not as precise, but as the TCU learns and adapts the shifting will get a lot more smoother as it has adjusted to your driving.

Usually the 09G transmissions will have problem most of the times relating to the software and not hardware. But then you never know what's wrong unless you find the root cause of the same. If the above does not fix the problem then their is a way to track the re-learn process as well by tracking the duty cycle of 6 solenoids which are responsible for the shifts. The max extent if it is not a software issue, then next step would be to check the valve body if it has any leaks from one side of the valve to other side, which may cause issue with the solenoids. But before diving too deep, the above suggested method should be tried first and be checked if their is some difference in any of the gears.

[audioholic]

How different is the shift behaviour in S mode compared to D? The S mode normally has higher shift points compared to D when the conditions are the same. If D is upshifting late due to some influencing factor, then I expect S to not be very different. In this case is S mode resulting in much higher shift points?