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Hi All, long post. It's been a few months since I've added to this but I can happily say I have a solution and made a controller for delaying the torque converter lock up, and what a difference it makes. No joke.
I know this thread didn't get as much attention as I thought it originally would have, which I found surprising though I think most don't know any different and are so use to engine and transmission performance how it is. For me this was an absolute deal breaker, because as previously mentioned I tried the throttle controller, cayenne trans coding, had the engine remapped but nothing corrected the reduced torque and lag around 3rd gear which really does affect how the car drives in general.
I also looked into having the TCM remapped however altering the torque converter lock up points wasn't possible. Everything else about the car is great just the TCM tune is 100% more orientated for keeping emission's low by keeping the engine out of its peak torque window as much as possible by default, and by having the TC lock so early in 3rd gear and at such a low speed ~30-32km's it does that just perfectly, BUT at the sacrifice of reduced torque, less acceleration performance and less acceleration response.

The controller completely eliminates the reduced torque and lag specifically in 3rd gear so now when accelerating in D3, the engine rpm can flare up so its sitting in its peak torque window immediately and the acceleration and boost is instant, and how it should be imho. D3 gear is used a lot during local / city / low speed driving or when slowing to approaching roundabouts / exiting roundabouts you are in D3 or when entering and and then going to re accelerate as you are exiting corners you would be in D3, or just accelerating or to over take these are the times you really notice the difference. Having the ability to accelerate effortlessly makes a world of difference on how the car drives and feels. The engine always had the power there, just it was being held back.

Previously when the TC would lock, the engine rpm is reduced down to around 1700rpm in D3. This is where the lag starts from, so when needing to accelerate from this point the engine is sitting well outside of its peak torque window. The result is having no where near as much torque that could be available so the engine lug's and lags until the rpm rise's to where boost is made, which on the CRCA engine peak torque isn't until 2500rpm.
The controller also smooths out some of the vibrations/clunk/jerky feels whilst in 3rd gear that is naturally there when the converter would have normally been locked, you would feel this when coming off and on the throttle in 3rd gear as the converter unlocks and locks, I first observed and confirmed this with VCDS when monitoring the torque converter status.

So how I did it.
First I reached out to all of the vendors that currently make torque converter controller to see if its something they wanted to tackle however most didn't want to look into it since the Touareg market is small, or they had other priority's so this wasn't going to move along as quickly as I would like. Also all of the current vendors make torque converter lock up controllers, not UN-lock up controllers which is what the Touareg actually needed. I knew how I wanted to controller to operate the "delaying and handing back over to the TCM" piece, but I needed information from the transmission canbus to achieve this, so I started researching everything I could about canbus systems and canbus hacking.

Once I had my head around that I built a canbus sniffer, so I could start collecting the raw canbus traffic and messages that are being communicated on the powertrain bus. I quickly realised how busy the canbus is on the Touareg even with just the ignition on, so trying to filter and locate the ID relating to the transmission and canbus message and byte specifically for the actual transmission gear selected wasn't going to be easy, but eventually I got there once I found some software that made reading the traffic a lot easier.
Once I nailed down the canbus ID, message and byte responsible for the "actual gear selected" that was one of the hardest part's done. So now with that data the controller is constantly listening to the canbus traffic and whenever D3 (and only D3) is selected, the controller see's that canbus message and then closes the contacts on two relays to divert the two wires that were going to the N443 lockup solenoid and now sends and completes the TC lockup circuit through a 50w load resistor to mimic a load on the circuit (this is required otherwise there would be an open circuit and subsequently P2757 would be flagged), as soon as the transmission shifts out of D3, the two relay's de-energise and contacts open again so the N443 solenoid circuit is handed back over and has continuity directly to the TCM as it normally would have. The only time the relays are energised is only when the transmission selects D3. Once the transmission shifts into D4 the torque converter locks up as it normally would have after a gear change has taken place, which is near on immediately. You hardly notice the torque converter locking up now since the gear ratio in 4th gear is more closely matched to the engine speed so it's very seamless comparing to the original TC locking up in 3rd gear it is very noticeable by the large reduction in engine rpm as is slips and modulates until the converter is locked.

Completing my validation testing, I was surprised that the TCM/ ECM didn't recognise that the TC was not locked in 3rd gear when it would have normally been commanding it (and that would have been my next hurdle to overcome if it did happen), since most TCM's are comparing the transmission input shaft speed to the engine speed to determine if there is an issue with the TC solenoid or TC operation since a locked TC speeds would be very similar to engine speed. I couldn't find any information specific to the Touareg on the logic or threshold before flagging a P2757, but I did find some info on the Toyota Aisin 6 speed transmissions, my only theory is the the TCM is not looking for a close match at such a low gear and speed, and is likely only looking for that in taller gears and when you would likely be travelling at greater speeds.

The controller is mounted neatly under the drivers seat, since this is where the TCM is located. I had to tap into the can high/can low wires, and cut the two N443 solenoid wires near the TCM connector. The controller is powered via a USB cable currently which makes turning off the controller easy so the TCM can function completely original if needing to. I will look at hard wiring the power supply soon and mounting a switch in the centre console.


View attachment 251223
Same TR80SD transmission, same AL1000 TCM 0C8 927 755. The canbus message relating to the actual gear selected info that the module is looking for will be the same across the entire 7P model range.

I will PM you soon.
Please count me in. If your solution works and I can acquire same....I may keep the car. If not then the Touareg has to go. I am sick to death of VWs ignorance and scant regard to customers real world concerns. Help!
 
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