Shift solenoid 2-3. Recently the dealer replaced the PCM, and before I wasn't having this code, but now I am. I'd rather not go back to them, as they were a PITA. I keep getting this code, I have replaced shift solenoid (did both while I was there), and I have checked and cleaned the ignition switch. What is there to do (by myself) next?

 

I just checked the fuse, reading 12 volts so that's good. How hard is the PCM to get to?

edit: pcm is easy to get to.

 

my question is, can i unplug the pcm without any repercussions? obviously battery will be unhooked...

 

Well, PCM is good. Maybe me re installing it will cure the problem :/ ha yeah right

 

So, reading up more on it, I think I'm gonna pull the pan, again, and check the wiring to the shift solenoids, even though I just replaced them.

Added information: I can clear the code, and then when I start and drive it, it will shift from 1 to 2 to 3, and about after 2 seconds after it shifts to third the check engine light will come on. With the CEL still on, I can shift into "2" and it will go to second gear, however if I go to "1", it will stay in second.

If I clear the code and shift it to "2", the light will never come on, of course until I put it into D or 3 and it shifts up. Hope this helps whoever help me.

 

Bump for more suggestions? Anyone?

 

Hoping for some answers on this...

 

You should be able to read the RESISTANCE of the solenoid coil. That would tell you that the wiring to and thru the transmission is good. If the resistance is good, there could be an issues with the mechanical part of the solenoid / valve body. Read it from the PCM Plug to the trans.

 

I don't think I'm understanding where exactly to test for resistance? At the PCM or at the Trans?

 

Not sure this helps but I had the same issue after the cam and stall were installed. Replaced the solenoid and it still came back. ended up having the code written out.

Good luck

 

FIY,

Action Taken When the DTC Sets


•The PCM illuminates the Malfunction Indicator Lamp (MIL) .
•The PCM commands third gear only.
•The PCM commands maximum line pressure.
•The PCM inhibits TCC engagement.
•The PCM inhibits 4th gear if in hot mode.
•The PCM freezes transmission adapt functions.
•The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
•The PCM stores DTC P0758 in PCM history

 

Bill, when you had the code, did it have all the symptoms? Like the 3rd gear take off and all that? How did you hav wit written out? By the dealer or a tuner?

 

After examining the schematic, you need to prove the electrical circuit good or bad. To do that, disconnect PCM connector C2 and find pin #47.

Remove the fuse ENG1 Fuse 19 and insert the meter probe on the side of the fuse that goes to the transmission Pin E. The other Ohm Meter lead will be inserted into Connector C2 pin# 47. That will allow you to read the circuit continuity thru the solenoid and the entire wiring circuit. The resistance of the solenoid coil should be 19 to 31 OHMS


Install the J 44152 on the transmission side of the AT inline 20-way connector.
Using the J 39200 digital multimeter (DMM) and J 35616-A , measure the resistance between terminal B and terminal E of the J 44152 . Refer to Automatic Transmission Inline Harness Connector End View .
Does the resistance measure within the specified range?
19-31 ohms
Go to Step 9
Go to Step 10

9
Measure the resistance from terminal B to ground, and from terminal E to ground.

Do both readings measure greater than the specified value?
250 K ohms
Go to Diagnostic Aids
Go to Step 11

10
Disconnect the AT wiring harness assembly from the 2-3 SS valve.
Measure the resistance of the 2-3 SS valve.
Does the resistance measure within the specified range?
19-31 ohms
Go to Step 18
Go to Step 19

11
Disconnect the AT wiring harness assembly from the 2-3 SS valve.
Measure the resistance from the component's terminals to ground.
Do both readings measure greater than the specified value?
250 K ohms
Go to Step 18
Go to Step 19



If the wiring and resistance readings are good, you probably have a tuning issue or the driver circuit for that function is bad.

I'm not a tuner but contact a good tuner and he may be able to tell you what needs to be tuned to prevent the code from popping up. Sounds like there is an illogical parameter causig it not to function.

The PCM applies circuit ground thru a driver circuit when certain parameters are set and allows operation of that solenoid:

Circuit Description
The 2-3 shift solenoid (SS) valve controls the fluid flow acting on the 2-3 shift valves. The 2-3 SS valve is a normally-open exhaust valve that is used with the 1-2 SS valve in order to allow four different shifting combinations. The solenoid attaches to the control valve body within the transmission. The 2-3 SS valve receives ignition voltage through circuit 339. The powertrain control module (PCM) controls the solenoid by providing the ground path on circuit 1223.

When the PCM detects a continuous open, short to ground or short to power in the 2-3 SS valve circuit, then DTC P0758 sets. DTC P0758 is a type A DTC.

I take back my comment about SHORT CIRCUITS because you can short the ground side of the circuit to ground and cause this failure and not burn up anything


Bill

 

Yes, and my tuner tuned it out. I guess it is not uncommon when a stall is introduced into the equation.

 

Hey, i am here in germany, and i have right now the same problem with my vette, that u have. What was the problem?
I change the solenoid, the pcm, check the wires......
If i drive NOT faster then 19mph, it works perfect, shifts up and down.... but if it switch to 20mph, the p0758 comes again