Subaru CVT Transmission Failure | valve body replacement

2012 Subaru Impreza Sport 2.0L DOHC H4 Normally Aspirated AT CVT Transmission P2764 + P0700

 

This article refers to a 2012 Subaru Impreza Sport 2.0L DOHC H4 normally aspirated AT CVT transmission with 105K. The transmission goes into a failsafe mode with CEL P0700 transmission failure MIL requested. Using a Snap-On scanner we can access the transmission computer to get more specific codes. The transmission computer stores a P2764 Lock up duty solenoid circuit low. ThIs code is for the torque converter lock up control duty solenoid which is a pulse width modulated solenoid, meaning it’s not a normal on/off solenoid which would be similar to a switch. This solenoid controls different ranges of torque converter clutch slip that’s indicated by a percentage of lock up applied. This is usually known as TCC slip percent. Since this is a CVT transmission there is already power lose through slip so the torque converter lock up is very important. This CVT transmission operates no different than your snowmobile or Polaris RZR with belt except the belt is a chain for the Subaru CVT transmission. Take a look at these pictures to have a better idea. 

SubaruCVTTransmissionInternalView

Cut away internal view of the Subaru CVT transmission

SubaruCVTChain

Subaru CVT chain, same concept as belt driven CVT transmissions.

Subaru CVT P2764 + P0700 Repair Procedure 

On to the repair for codes P2764 and P0700 codes. The test is to ohm check the lock up control solenoid, this is a two wire solenoid, the bulk head electrical connector and can be accessed from the top of the transmission. You just need to remove the air box and dog bone mount for easy access. You will most likely find an open circuit or high resistance (k-ohms). You can also just clear code, test drive and see if the code comes back immediately. If so then I would consider this a hard code and solenoid failure is most likely what’s wrong with it. It would be very uncommon to find a broken wire or burned up transistor within the computer. Unfortunately, the solenoids are not available separate from the valve body. The valve body has to be replaced with the solenoids. I have seen this in Volvo and VW AT transmission valve bodies but this is new for Subaru. Volvo and VW will state the solenoids are dynamically tuned to the valve body and cannot be sold separate. So, as for the repair it’s pretty straightforward. Remove the transmission, remove upper valve body cover and replace valve body assembly. I recommend to remove the pan and change the CVT fluid also, probably takes about 6-8qts with pan removal and valve body replacement. This repair runs about $1800-2000 at our shop as of 8/24/2017. Take a look at the picture gallery below, contact us for appointments or comment below if you have any questions. Thanks for reading, cheers. 

This post was written by: Martin Hand

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Martin Hand

About Martin Hand

ASE Certified L1 Advanced Mastertech. Martin Hand has over 15 years experience in Asian and European Import Auto Repair. Specializing in electrical diagnosis, engine performance, AT/MT transmission repair/rebuild. Martin is also pursuing a degree in Computers Science & Information Systems starting at Portland Community College while he plans to transfer to OIT. Certified in Java application level programming, experienced with other languages such as PHP, Ruby, JavaScript and Swift. Martin has future plans of automotive diagnostic software development.

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