Trans not working but not blown... Weird codes and wont shft into gear. XHP + Custom E50 Tune

[dylanhartman]

I recently took my 2020 Supra to a shop and had them tune my trans with XHP. Since then, I’ve gotten multiple codes:

420411 Gear ratio monitoring in fixed gear, clutch B, disrupted
421362 Gear ratio monitoring: all clutches implausible
CDC10D Signal (status of transmission gear selection, 0x39A) invalid, transmitter GWS
CDC12F No message (torque request, 0xB0 DME receiver, EGS transmitter

My car threw a “drivetrain malfunction” code on my car’s dash and screen, and threw me into neutral and can’t go back into gear. I had these codes cleared and it happened again about 30 miles later.

Has anyone ever seen this? I'm stuck because I cant find any info about this online and it could be 1 of 10 things... Not sure what to try first.

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[Thraxbert]

You need to ask the shop exactly what they did:
Was anything touched, mechanically?
Did the shop play with the neutral switch on the driver's side of the trans?
Did they touch the plug on the back of the transmission?
What XHP stage did they flash?
What settings did they choose?


I have sincere doubts that there are more than a handful of shops in the entire country that are competent with XHP.

And your very first step should be to flash the transmission back to stock and see if this behavior persists.

Do not use a shop to flash car firmware. Odds are overwhelming that they do not know what they are doing. Learn to do it yourself so you can control every variable, or don't do it.

 

[dylanhartman]

You need to ask the shop exactly what they did. I have sincere doubts that there are more than a handful of shops in the entire country that are competent with XHP.

And your very first step should be to flash the transmission back to stock and see if this behavior persists.

Only issue is, this shop is 3 hours away so I cant take it back to them, and I'm not the most knowledgeable in this situation being that I dont have the license myself for XHP.

Although I did just email XHP so we'll see what I can do

 

[Thraxbert]

Good luck with XHP. Be prepared to have your car towed 3H back to that shop. At the very least, you need to call the shop and learn every minuscule detail about what work was performed.

 

[dylanhartman]

Good luck with XHP. Be prepared to have your car towed 3H back to that shop. At the very least, you need to call the shop and learn every minuscule detail about what work was performed.

Might be a dumb question but is it more worth it for me to just take it into Toyota and ask them to flash everything back to stock? Even if this means I have to re-bench unlock it, I dont care. Better than 6 hours of towing potentially...

 

[SavagePassenger]

You could probably get Toyota to do that, but like you said if they reflash the ECU as well as the TCU you would have to bench unlock again and get your tune reflashed.

I would definitely get details from the shop though - were they doing a custom XHP map? You should be able to check what was installed if you have the app or can use it with what you purchased. I can't imagine the preset tune would cause this but not sure. I got the preset tune/license package from XHP so I've only installed the stage 2 / stage 3 maps with a few of the basic flash settings you can customize. Like Thraxbert said I would wanna know exactly what the shop did.

 

[zrk]

If you're 100% certain that you didn't blow out a clutch (which is 1000% possible with stock trans on XHP), then TCU data is probably corrupted and needs a reflash.

Rather than tow the car to a shop to do something than can easily be done by an end-user, buy a dongle, buy a license, and do it yourself.

You need a dongle and the license anyway to adjust things, so you might as well just do that.

 

[Yabai]

If you're 100% certain that you didn't blow out a clutch (which is 1000% possible with stock trans on XHP), then TCU data is probably corrupted and needs a reflash.

Rather than tow the car to a shop to do something than can easily be done by an end-user, buy a dongle, buy a license, and do it yourself.

You need a dongle and the license anyway to adjust things, so you might as well just do that.

Sorry don't mean to hijack. Does that mean we shouldn't be using XHP on stock trans?

 

[Syeeee]

iirc xhp tcu flash is very easy install at home with a doggle.

 

[KBGT]

Sorry don't mean to hijack. Does that mean we shouldn't be using XHP on stock trans?

We should not be doing any modifying of our stock vehicles if we are not prepared to accept the possibilities. Does XHP kill every stock trans, no absolutely not. Can it help kill a stock trans, absolutely. Is XHP right for your car, it depends lol.

More power, miles, races, temp, etc it all plays in the probability of failure equation.

 

[Kolme]

I vote for the buy license, get the dongle, reflash, get refund from shop, blow clutch, blame zrk and trade in car as slightly used.

 

[zrk]

Sorry don't mean to hijack. Does that mean we shouldn't be using XHP on stock trans?

No. But if you fuck with the car -at all- be prepared to pay to fix it.

 

[Thraxbert]

Sorry don't mean to hijack. Does that mean we shouldn't be using XHP on stock trans?

No. It means there are specific settings that a stock trans should not use, and we do not know what this shop did.

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