No 2nd gear,high rpm at 1rts , p0775 code " check transmision" E

[fabrizio]

Hi!

I've been reading about this issue on the site , very helpful info.
I need a tip of how to handle this situation. thank you!!

2001 LS v8 @110,000 miles-
p0775 code.

I was planning to maintenance the suspention but it had to wait.:frown:


The transmision was shifting right , sometimes a little strange from 1rst to 2nd, the upper shifting was fine and smooth.

Today i note that it develop a high rpm almost hitting the engine red-line without shifting to 2nd, it does not shift unless i let up on the accelerator.
it shifts fine and smooth if you run slow.

looks like i loose 2nds if i move the lever.

Some minutes after driving ,the warning " check transmision" appears on the dash screen followed by an "E" where the shift lever indicator is.
CEL code " p0775"

I read this post about the 5r55 repair also the Andy's fix "servo bore" and Sleeve from sonax.

the symptoms point out to "servo bore" issue.

What do you think about ??


thank you!

 

[stumpie]

I think you are about to have to decide how much you like your LS - most trans techs wont open her up w/o an agreement to rebuild -> ~$2k

 

[joegr]

I think you two are definitely jumping the gun here!
Your transmission may have mechanical problems, but it might not. P0775 is a code for an electrical problem. Something is wrong with the solenoid "B" coil, the wiring to it, or the PCM. I would do the pin-point tests to determine which of the three it is and then repair that. Only after the P0775 code/problem is gone will you be reasonably able to tell if there is or isn't anything else wrong. (I do believe that failure of the solenoid "B" circuit is enough to cause all of your symptoms so far.)

 

[fabrizio]

thank you for reply!

Yes, I really love the car.

So to test the solenoid should i take off the solenoid pack ?

is there any easy access wire to measure directly?

best regards!

 

[joegr]

You can unplug the connector from the PCM and measure there. That will either tell you that the wiring and the solenoid coil are okay, or that one or the other has a fault. If it's the latter, then you can disconnect the plug at the transmission and do point to point testing on the wiring. You really can't get to the solenoid to measure it directly, without removing it from the transmission. If I removed it, I would just go ahead and replace it with a new one.

 

[fabrizio]

Hi

Ty for reply.

I got the pcm a/t connector pinout but it does not show the pin name.:Bang

Could you help me ,pls?

Connector C175b A/T

best regards!

*idk why the pic is resized. >_<

 

[fabrizio]

15A fuse F6 (transmision fuse) removed from fuse box under the hood.
connector c175b removed from PCM

Positive tip to fuse holder and the other one to the connector c175b pin number :

Shift Solenoid A pin 1 - 26.3 ohms (16-45ohms)
Shift Solenoid B pin 2 - 26.3 ohms
Shift Solenoid C pin 3 - 26.3 ohms
Shift Solenoid D pin 4 - 26.3 ohms

PC solenoid A pin 7 - 5.6 ohms ( 3.3-7.5ohms)
PC solenoid B pin 13 - 5.6 ohms
PC solenoid C pin 12 - 5.7 ohms

TCC solenoid pin 5 - 11.5 ohms ( 9-16ohms)

I found a chart where the measurements fit in range " (value) "

Atleast it seems to be ok. No shorted or open. idk if it work properly.

I don't figure it out how to measure the voltage drop on solenoids with the solenoid pack installed and switching between them.

Any ideas ?

Could I power up the solenoid by the cable harness without any damage ?

Best regards!

** I have an ALLDATADIY account, it has been helpful but again it shows me a wrong wiring connector, it does not match.

 

[joegr]

The voltage drop test only has meaning if the PCM is turning them on and off. If you use a cable harness to power them, you will only be proving that your cable harness is good. With the right scan tool, you can tell the PCM to turn the solenoids on and off as needed for testing.

 

[fabrizio]

Thank you joegr , very helpful !

So with the resistance test done , what else could I check to prove a solenoid failure?

best regards!

*I'm downloading the TBS for p0775.

 

[joegr]

Did you check resistance between all of the solenoid wiring and the car's ground? (Should read open circuit on all.)

 

[Telco]

The voltage drop test only has meaning if the PCM is turning them on and off. If you use a cable harness to power them, you will only be proving that your cable harness is good. With the right scan tool, you can tell the PCM to turn the solenoids on and off as needed for testing.

I would think that this would also prove the solenoids to be good as well, eliminating them from consideration as the cause of the problem. However, while I understand how solenoids work my troubleshooting understanding of them is not so good so I am not sure if I speak truth or fertilizer here.

 

[joegr]

I would think that this would also prove the solenoids to be good as well, eliminating them from consideration as the cause of the problem. However, while I understand how solenoids work my troubleshooting understanding of them is not so good so I am not sure if I speak truth or fertilizer here.

Yes, I think it is just a double check to determine if the PCM is at fault.

 

[fabrizio]

Hi!

The solenoid are not shorted to ground,double check done.

Today I ran the car again to reply the issues.

Running normal without overtaking it shifts normal.No CEL or tranny warning.
Engine braking works ok except when doing 3rd to 2nd,to engage 2nd it delays more than before.

In a stop and go event :

If i press the acelerator full down it develops a hi rpm near 4k-5k rpm some seconds before to change to 2nd, after 2nd gear it runs and shift smooth.
After doin that ,the "E" tranny message apears and 2nd is lost until turn off-turn on the car.If i repeat this test the CEL come ON.

I assume the solenoid pack works ok because it does not develop the issue when driving normal(No overtaking).
shorted or open solenoid coil test done. The resistance value is in range.Ok​

Some research shows that changing the solenoid pack does not solve the problem.
In some cases the "servo bore O-ring fix" does not work because the bore presents an abnormal wear like oval-egg shape so the rings don't close properly.

I'll go for the sleeving bore fix , in my opinion it will last longer and it has to be done soon or later.

--What do you think ??

Best regards!


From Andy's Fix symptoms:

Symptoms and other common things to know about the worn bore problem.

1. Transmission will not hold in OD/5th gear. It gradually gets worse. Eventually the transmission will not shift back into OD unless you were going down an incline. It will shift out of OD after any sign of load especially after the transmission warms up.
2. Transmission will shift fine when it is cold but then will exhibit shifting issues after it warms up.
3. Transmission will not shift out of 1st gear into 2nd. The engine will red-line and not shift unless you let up on the accelerator. It will shift from 1st to 2nd if you accelerated very slowly.
4. A combination of one and or two would produce a flashing OD light and eventually throw a service engine soon light.
5. Codes returned for the described situation P0775 Pressure Control Solenoid B Circuit Malfunction. Others such as P0732 incorrect gear ratio 2nd gear, P0733 incorrect gear ratio 3rd gear, P0735 incorrect gear ratio 5th gear, are also common.
   [*]Problems may occur as early as 70,000 miles and as late as 180,000 miles depending on driving habits. mine has 100k miles

 

[fabrizio]

Hi!

We solved the issue.

-Overdrive servo replacement
-Internal parts replacement (band/clutch pack/etc..)
-oil pump valve
-Transgo shift kit installed.