Will not shift automatically code: P0758

[qsp01]

Last night I noticed that the transmission seemed to be stuck in a high gear as it was not down shifting. I was able so shift by selecting the proper gear on the shifter. The SES light came on. Checked the code today to see a P0758 and took a quick drive around the parking lot and it seem to be shifting alright. It is raining today so I haven't been able to check anything else. The XUV just turned 120K and the transmission was replaced around 60K. The previous owner was a young woman who drove it pretty hard. It was her first car! I searched the forums and didn't see this exact symptom and also saw that sometimes it was related to the ignition switch and even the CPAS. It seems that most likely cause is the shifting solenoids. I gather that you must pull the pan to get to them. I once had a ford that developed shifting problems and it turned out to be a back vacuum line. Any suggestions from the experts would be greatly appreciated!


Best Regards, Doug

 

[BlazingTrails]

P0758 - OBD II Trouble Code


Auto Systems and Repair


Shift Solenoid B Electrical
OBD II Fault Code

• OBD II P0758

Fault Code Definition

• Shift Solenoid B Electrical

What does this mean?
The purpose of the automatic transmission is to match the engine's optimum power and torque characteristics to the driver's desired rate of acceleration and speed by auto-selecting different gear ratios or 'speeds' to power the wheels. Shift solenoid B enables the transmission to shift from 2nd gear to 3rd gear. It does this by re-directing the flow of the transmission fluid which changes the position of the shift valves in the valve body.
When the code P0758 is set in the Powertrain Computer, it means that the Powertrain Computer or PCM is not seeing the specified rpm change that occurs during a shift from 2nd gear to 3rd gear. It's also not seeing the correct increase in road speed from the vehicle speed sensor.

You can try doing a PCM reset and see if it resets, but likely you just need to replace the shift solenoids inside the transmission pan. I know Auto zone carries them I am sure everybody else does also. it is pretty easy to do so don't be nervous.

 

[qsp01]

Thanks for the details on the P0758 ... I also notice that the transmission seems to always shift into overdrive sooner than I would think it should and then it gets pretty sluggish. I will do a search to see that is involved with changing the fluid.

 

[qsp01]

The transmissions has been doing fine the last couple of weeks .. thought it was low on fulid at first but it was not up to temperature. I added about a pint and then realized that it wasn't low and so I sucked it back out from the dip stick with my handy oil extractor that I got from west marine. I went ahead and ordered the three shift solenoids, a dorman pan with drain plug and a ac delco filter. Will go ahead and drop the pan and see what I find over the next couple of weeks...we still have family in town so I've been tied up on the weekends. Also thinking of the method to switch out all of the fluid by pulling the cooling line but not sure yet. Looking to use Valoline Fluid as you can get it for $20/gallon at auto zone.