C1201 and P0990 codes plus shudder after trans milkshake

[AurionX2]

Long time no see, posting from sunny Brissie now 🙂 This was posted on TN earlier. Here it goes:
2007 Aurion SX, 195000kms, bought private 5 months ago at 187000k as a beater. 3rd Aurion in the family, cause the other 2 are still going strong. All good except for shot rear shocks (todo) and a slight transmission shudder that mostly happened in 5th or 6th gear under load at low-ish speeds. Until one day when the temp went up suddenly in city traffic, unlucky: thermostat went and when I got home (after letting the car cool down and topping up with distilled water) I saw some weird gunk when I took the rad cap off. When I disconnected the return transmission line lo and behold, some dark brown milky stuff came out. Replaced the radiator, thermostat (pita to take the housing off), rad hoses (the heater core ones are fine, skipped them for now), drive belt, then went for the complete trans service with pan drop, filter & gasket and flush using Valvoline Maxlife, then fluid level check. Bloody milkshake, it took 19 litres to get most of that crap out.
Anyway, after all that the shudder didn't go away, if anything it got worse(?), plus some P0990 pending code, along with Check VSC, check engine and ABS/TC lights startede to come on. Blamed the fluid (up until now I've only used Penrite ATF LV, Aussie made to WS spec in the other 2 cars, but too expensive post-covid) so I said: ok, will go genuine Toyota WS. So just did another pan drop today plus flush using the Toyota stuff, 12 litres all up. Took the opportunity to change the dog bone (almost shot) and the 2 side mounts (trans side was shot, the other one felt ok). The drain fluid was still looking a teeny tiny bit like strawberry milkshake after maybe less than 200km all suburban short drives, wtf?
So here I am: fresh Toyota WS fluid, the shudder is still there and now I have C1201 and P0990. Thing is, I might have missed C1201 code in during previous reads because I wasn't looking for engine codes, only transmission related. Drive experience after the 2nd flush: I can't tell the car feels better with Toyota fluid, the shudder is still there even after adding Lubegard instant shudder fix snake oil in there, will try tomorrow with the 2nd tube. However, this time around there's a slight change in behaviour: the car now actually holds 6th speed under load at 60-65km/h (but it still shudders!), while before it was bouncing between 6th-5th-6th-5th continuously. Really annoying this gear hunt...
And the question: what to do about the C1201 and P0990, short of finding a reputable specialist in my area that can work his magic? Is C1201 rather generic and it'll go away if P0990 goes away? Or are they separate issues?
Other than the issues above, the car drives exceptionally well ta-daa!

Edited April 22, 2023 by AurionX2

[campbeam]

17 hours ago, AurionX2 said:

The drain fluid was still looking a teeny tiny bit like strawberry milkshake after maybe less than 200km all suburban short drives,

Obviously this is not what you want to see. I would be seriously considering doing another change of atf and replacing the filter again. https://www.clublexus.com/forums/rx-3rd-gen-2010-2015/966724-p0990-transmission-problem.html 

Initial step may be to drop the transmission pan and inspect/clean. Same for the filter. Mineral turpentine is recommended as the cleaning agent. https://www.transmissionbench.com/cleaning.html Decide whether a change of atf is applicable at this point in time. I would also be thinking about doing a lot longer suburban drives then maybe some highway driving to get the ATF up to full operating temperature for longer and more circulation through the filter.

I did a Google search using a search term of C1201 Toyota Aurion. Following urls are worth a read. Possibly the transmission shudder could have triggered this code or maybe something else. Something for your consideration.

https://ricksfreeautorepairadvice.com/c1201-toyota/

https://mechanicbase.com/trouble-code/c1201-toyota/

[Twixter]

Heyo. Sorry, I'm not able to provide much input on this. But you're in Brissy now? Welcome!
If you're looking for a more local Aurion community, you can join us at Brisbane Aurions: https://www.facebook.com/groups/brisbaneaurions

We even have a cruise coming up on Sunday!

[Tony Prodigy]

On 4/22/2023 at 10:26 PM, AurionX2 said:

Long time no see, posting from sunny Brissie now 🙂 This was posted on TN earlier. Here it goes:
2007 Aurion SX, 195000kms, bought private 5 months ago at 187000k as a beater. 3rd Aurion in the family, cause the other 2 are still going strong. All good except for shot rear shocks (todo) and a slight transmission shudder that mostly happened in 5th or 6th gear under load at low-ish speeds. Until one day when the temp went up suddenly in city traffic, unlucky: thermostat went and when I got home (after letting the car cool down and topping up with distilled water) I saw some weird gunk when I took the rad cap off. When I disconnected the return transmission line lo and behold, some dark brown milky stuff came out. Replaced the radiator, thermostat (pita to take the housing off), rad hoses (the heater core ones are fine, skipped them for now), drive belt, then went for the complete trans service with pan drop, filter & gasket and flush using Valvoline Maxlife, then fluid level check. Bloody milkshake, it took 19 litres to get most of that crap out.
Anyway, after all that the shudder didn't go away, if anything it got worse(?), plus some P0990 pending code, along with Check VSC, check engine and ABS/TC lights startede to come on. Blamed the fluid (up until now I've only used Penrite ATF LV, Aussie made to WS spec in the other 2 cars, but too expensive post-covid) so I said: ok, will go genuine Toyota WS. So just did another pan drop today plus flush using the Toyota stuff, 12 litres all up. Took the opportunity to change the dog bone (almost shot) and the 2 side mounts (trans side was shot, the other one felt ok). The drain fluid was still looking a teeny tiny bit like strawberry milkshake after maybe less than 200km all suburban short drives, wtf?
So here I am: fresh Toyota WS fluid, the shudder is still there and now I have C1201 and P0990. Thing is, I might have missed C1201 code in during previous reads because I wasn't looking for engine codes, only transmission related. Drive experience after the 2nd flush: I can't tell the car feels better with Toyota fluid, the shudder is still there even after adding Lubegard instant shudder fix snake oil in there, will try tomorrow with the 2nd tube. However, this time around there's a slight change in behaviour: the car now actually holds 6th speed under load at 60-65km/h (but it still shudders!), while before it was bouncing between 6th-5th-6th-5th continuously. Really annoying this gear hunt...
And the question: what to do about the C1201 and P0990, short of finding a reputable specialist in my area that can work his magic? Is C1201 rather generic and it'll go away if P0990 goes away? Or are they separate issues?
Other than the issues above, the car drives exceptionally well ta-daa!

Hey Adrian. Did you make the move to Brisbane ? You were in Sydney previously right ?

Did you get any info back on TN ?

So the root cause of the milkshake was a bad radiator core ? That's always a worry when you have both engine coolant and transmission fluid sharing the same unit albeit separate circuits.

I wonder which circuit gives way first.. I tend to think the coolant side may, especially if the cooling system has been neglected or coolant is compromised which can eat away at the core metal. 

I suspect the transmission may need a bit more TLC than fluid flushing. Maybe the solenoids need to be removed and cleaned also. Milkshake is messy. It get into everything. 

[Smithy_M63]

I think you'll find that you will have to replace the clutch pack in the trans. They do not handle water at all. Sorry for the bad news. Water takes out the friction material and thats the cause of your shudder

[Tony Prodigy]

2 hours ago, Smithy_M63 said:

I think you'll find that you will have to replace the clutch pack in the trans. They do not handle water at all. Sorry for the bad news. Water takes out the friction material and thats the cause of your shudder

Hey, I never thought of that. Yes, I agree. Those clutch packs are pretty brittle unless they are saturated with tranny fluid.

Just like an automatic transmission that's been sat around for years or decades will most likely need a rebuild. If the clutch packs dry out, same thing. Not cheap to rebuild either to be honest. But yes, when you've had a catastrophic situation like water contamination, chances are the tranny will be on the way out.

I'd just try and find a replacement low mileage transmission and swap it out rather than waste time with flushing etc.. 

[AurionX2]

Thanks everyone for chipping in, appreciate it 🙂

Tony, we moved from Melbourne at the end of 2021.

Matt, thanks for the heads-up on the meeting, but since I don't have facebook I might have to ask my wife to join the group, we'll see, in the end she's driving an Aurion so she has a duty of care in this respect 🙂

Ashley, I've done 2 flushes by now and dropped the pan 3 times to clean it up. All up would have been around 28 or so litres of ATF Even after the latest flush. I was tempted tbh to replace the filter again, but not anymore. Oh and before I forget: I'm a big fan of Car Care Nut, so knowledgeable and honest, have you watch the video when he bought his wife a new car? Priceless 🙂 

Peter, that's sort of where it's heading, let me explain it. In the meantime I added the 2nd instant shudder fix tube through the refill hole which, after a few hundred kms of combined suburban and freeway driving, didn't seem to fix anything at all. However, today while driving around western suburbs checking wreckers & what not, I noticed the check VSC, engine light and ABS lights all went out. Plugged the ODB tool, erased the C1201 and P0990 errors (now I'm 100% sure C1201 was triggered by P0990) and, after probably a dozen of so stop / starts the error hasn't come back on. Fingers crossed the valve body is still good overall!

Now, how does the car drive? Apart from the shudder under load and slight lurching when accelerating sometimes, it performs exceptionally well haha! Very responsive when accelerating, smooths shifts, no flare, no overheating, it all seems to be pointing to the torque converter going. I've also changed my driving habits, I spend most time in sport mode now: start from 3rd gear and shift up & down as required, trying to keep the engine in a rpm range that doesn't trigger the shudder. 

I think I'll try a stall speed test tomorrow as documented in the U660E manual, see the screenshot.

Speaking of torque converters, here's a great video:

 

The most difficult part is to find a shop that will want to put in a replacement transmission, or only the torque converter, without charging an arm and a leg. Most places I tried are simply not interested in the job, they're prolly doing well with standard service and the odd trans cooler installation. Is this a Queensland thing? Ever since we moved we've seen so many occasions when you're asking for quotes (plumbing, electrical, concreting etc) and it's incredibly difficult to get anything done, as if everyone is sitting on a pile of cash and just can't be bothered! Different to Melbourne and vastly different to my overseas place of birth  🤣

If I get the transmission sorted I'm tempted to keep it, everything else works on it as it should and it burns no oil, quite remarkable for an engine approaching 200000kms. Will keep you updated with the progress

Edited April 29, 2023 by AurionX2