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I had a full transmission rebuild except the electronic part, around 6 months ago, because I had a gear slipping from 3d to 4th. I also changed the hydraulic torque converter. After that, I only drove for 8K miles.
I had no problems with the transmission whatsoever, everything worked smooth and perfect. 2 days ago, I started the car, drove to the highway and accelerated fast. At around 60 mph, the car stopped accelerating but revs were still going up as if I was reving in Neutral. There was no mechanical noise, no bumps, nothing. I stopped, switched the car off. All gears shift on the dashboard perfectly and you can actually hear the click when they change, however the car won't move. Parking works fine.
I would of brought it to the guys who rebuilt the gearbox, since I still have a warranty, however, this all happened in a different country since I took the car to Spain.
Took it to the workshop. The diagnostics show two errors: P0717 - Input/turbine Speed Sensor Circuit no signal.
P0894 - Transmission Component Slipping or wrong gear.
There is no oil leak. Drained the oil, the oil is clean, not burnt, no metal shavings. First they suggested it to be the mechatronic the electrical part. However, usually the car still moves in emergency mode with this problem, but mine won't move. Also, this problem doesn't appear out of nowhere usually.
Another expert suggested that it's the oil pump that went out so there's no pressure and suggested a full rebuild again and change the hydraulic torque converter again.
Perhaps someone faced this problem before. Please help cos everyone suggests different.
Code P0717 is triggered when the transmission's Input Speed Sensor isn't providing a signal. This is a critical problem because without this signal, the TCM cannot properly shift the vehicle from gear to gear as the vehicle needs to change speed and rates of acceleration. Need to check/replace conductor plate have an independent check it out and seek reimbursement from original shop.
Code P0717 is triggered when the transmission's Input Speed Sensor isn't providing a signal. This is a critical problem because without this signal, the TCM cannot properly shift the vehicle from gear to gear as the vehicle needs to change speed and rates of acceleration. Need to check/replace conductor plate have an independent check it out and seek reimbursement from original shop.
Thanks! In 90% of the cases, 0717 error means replacement of the conductor plate. However, in this case, the car goes into emergency/limp mode. I had this problem with my wife's ML and this problem was occuring for two years - limp mode, gears don't change. Turn it off then on again, and drive without any problems untill it didn't wanna get out of the limp mode and had a big knock when changing gears. I changed the plate and everything was fine.
However, in my case, the car stopped moving suddenly whilst accelerating. No limp mode. This shouldn't happen of ot was problem with the conductor plate. I was also told to unplug the main connector to the transmission, and if after that the wheels would start to spin in the limp mode, then it's defenitely the conductor plate. We did it, but nothing changed.
Your input shaft hall sensor is shot. As the tranny sees it- No signal from input shaft means engine is not turning over therefore no action by the transmission. As mentioned above me- replace conductor plate- an 07 has a ver 2 conductor plate so alternatively you might want to send it out to one of those rebuilders that will repair your board and no coding will be required. A new conductor plate will require scn coding at least. At most If old plate cannot be read you will need to replace the valve body and the conductor plate as they are mated from the factory.
Your input shaft hall sensor is shot. As the tranny sees it- No signal from input shaft means engine is not turning over therefore no action by the transmission. As mentioned above me- replace conductor plate- an 07 has a ver 2 conductor plate so alternatively you might want to send it out to one of those rebuilders that will repair your board and no coding will be required. A new conductor plate will require scn coding at least. At most If old plate cannot be read you will need to replace the valve body and the conductor plate as they are mated from the factory.
Thanks for a reply! I understand what you're saying since I had this problem with my wife's ML W164. I had to change the conductor plate. However, as I mentioned above, when a problem with a conductor plate occurs, the car goes into a limp mode and usually you can drive it for a long time just restarting the engine. It doesn't occur suddenly like in my case and doesn't lead to car being totally paralised. Could it be the problem with the transmission oil pump?
your wife's car prolly had a different problem - namely one where one or more of the turbine speed sensors on the conductor plate was intermittently malfunctioning resulting in tranny going into limp mode stuck into a single lower gear (usually 2nd) and check engine light. most of the time it is the y3/8n1 sensor in the center of the conduit plate.
i believe your issue is that a far more important sensor has failed - permanently - the one that detects the engine (tranny input shaft) rpms. if the transmission believes the engine is not turning it will not do anything.
if transmission pump has failed (also a possibility, but less likely since no input shaft speed detection has nothing to do with oil pressure) you can interrogate it with star/ das and observe oil pressures to determine if so.
your wife's car prolly had a different problem - namely one where one or more of the turbine speed sensors on the conductor plate was intermittently malfunctioning resulting in tranny going into limp mode stuck into a single lower gear (usually 2nd) and check engine light. most of the time it is the y3/8n1 sensor in the center of the conduit plate.
i believe your issue is that a far more important sensor has failed - permanently - the one that detects the engine (tranny input shaft) rpms. if the transmission believes the engine is not turning it will not do anything.
How would you suggest I can make sure it's a problem with that sensor? Is there any way of testing it? Or shall I disassemble the gearbox first and look for any mexhanical problems? I'm sure you understand that I don't want to just change the conductor plate and then if the car won't go, I'll be really dissapointed. What do you think about the oil pump in the tranny or the hydraulic torque converter? Could that be the problem as suggested by some people?
your wife's car prolly had a different problem - namely one where one or more of the turbine speed sensors on the conductor plate was intermittently malfunctioning resulting in tranny going into limp mode stuck into a single lower gear (usually 2nd) and check engine light. most of the time it is the y3/8n1 sensor in the center of the conduit plate.
i believe your issue is that a far more important sensor has failed - permanently - the one that detects the engine (tranny input shaft) rpms. if the transmission believes the engine is not turning it will not do anything.
if transmission pump has failed (also a possibility, but less likely since no input shaft speed detection has nothing to do with oil pressure) you can interrogate it with star/ das and observe oil pressures to determine if so.
Sorry, didn't see your reply regarding the oil pump.
first read the tranny with star/ das. if you have no pressure at the solenoids - your pump is bad. my guess is you will find pressure to be fine.
next would be to replace the conduit plate. in my mind that would fix the issue.
if it still doesnt work after that a tranny tear down to look for mechanical problems is in order.
that would be my way of approaching the problem
Just visited a workshop which specializes only in automatic transmissions. They said that it's most definetely the pump or in worst case the input shaft. They said that the conductor plate problems don't paralise the car, and if you unplug the tranny (like I did), wheels should spin in a limp mode, since you unplug the electronical part. In my case when I unplugged it, nothing changed. Not sure if I remembered correctly, but I think they also said something about the Reverse gear should be working if the problem with the electrics of the tranny.
10-18-2015, 10:39 AM
, any one knows please 
