I drove 3 miles down the road when my transmission lost power is the best way I can describe it. While everything on the dash was fine and indicated D for Drive, the car was in neutral and the throttle only revved the engine. I had to restart the car to get the transmission to work again but it failed a hundred feet later; reverse didn't work either. There were no warning lights or anything from when I had power going to my wheels to not having power which makes me worry a little bit more. In terms of the transmission, there were no leaks from what I saw, fluids were good, and the engine ran smoothly. I'm leaning more toward an electrical issue as there were no warning lights even though something is wrong; maybe something wrong with the TCU/GCU or other electricals. I'm happy to hear any opinions or suggest potential root causes, thank you.

After some digging through this forum, most posts related to transmission involved the shift being stuck in reverse or neutral but can't park; this is a completely different issue. If there is a thread that can point me in the right direction that'd be a big help. Hopefully nothing too serious.

I drive a Standard 2004 Crossfire with an automatic transmission if that matters. Thanks again.

 

Do you have access to a scanner to see what DTC codes have been set if any. Usually the first thing to check is the RCM.
-Jerry

 

https://www.crossfireforum.org/forum...-no-start.html

 

Thanks for the info. It's not a no-start issue but this could be helpful if I need to check the relay for bad contacts.

 

I had to put a transmission in mine. It did the same thing.

 

Error codes: P0715 and P0730. Both were noted as pending on the ECU which is why I never got a check engine light.
P0715: Input turbine speed sensor circuit 'A'.
P0730: Incorrect gear ratio.
I'm led to believe that the bad sensor is leading to an incorrect gear ratio which didn't make sense to me at first with an automatic transmission. I think because of the bad sensor(s) the TCM or PCM doesn't know the MPH or RPM of the engine and doesn't know when to shift. The computer then disengaged the transmission entirely but not to limp home mode probably because it couldn't. Worst case it is a TCM failure, torque converter failure, or electrical damage in hard-to-reach areas.

 

Input turbine speed sensor. Is this the speed sensor on the conductor plate?

 

Bad connection or speed sensor click on this link for Crossfire with the same problem and be sure to watch the video: P0715 DTC and correction

Trouble shooting steps are in the service manual for the P0715 code.

If the electrical connection at the transmission is leaking oil I would try fixing the leak before dropping transmission pan as cleaning and stopping the oil leak may correct the P0715 code. You will need to clear the codes with your scan tool. I don't think they clear by themselves.

IF you decide to buy the conductor plate to effect repairs I would purchase the complete plate with the valve, sensors and solenoids, not just the plastic plate. It's your call, but why take a chance on the problem being just in a bad connection. The sensor itself may be bad.

 

I got the manual pages for both error codes but the thing is that the codes were pending probably from the TCM sending them but I don't think I can access and clear the error from the TCM directly. I may have to unplug the battery for a bit to see if that clears it. Thanks for the video example and suggesting I get a conductor plate kit if that is the problem. I shall search once more for the source of thine issue.

 

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While you have all that apart, check the wiring to the TCM for trans fluid wicking up into the TCU. Good luck!


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No fluid crawling up towards the TCM, electrohydraulic connection isn't leaking either. Problem seems to be inside the transmission.

 

Are you making the repairs or taking it to a shop? Either way use the correct fluid Pentosin ATF 134 red. It is made by Fuchs in Germany.

I mention this because most shops will not have that, but will dump Dexron into it. Buy the fluid yourself so you know it is correct and be certain that it is put into the transmission.

 

We repair cars ourselves, my dad has been working on cars his entire life and dedicates an entire garage space with all his tools, lifts, and accessories; he knows what he's doing. He brought up the transmission fluid and that I had to pay $150 for 10 quarts or something ridiculous like that. The only time he needs to take cars into a shop is when he doesn't have expensive specialty parts that may only be used once in the car's lifetime. That's another reason he doesn't have STAR diagnostics because it's not necessary for him to fix the problem. The DTC is all he needs to lead him in the right direction.
We concluded that the issue was the conductor plate which is what we plan to replace.

 

Pentosin ATF 134 is the Mercedes recommended fluid. Use the cheap stuff if that is what you want. It is your car.