AcIdBuRn02ZTS

Hey alls...

Working on a 00' Hoe 130k on the clock... Left for work the other day and when I came to a stop, cel lit up... Tried to take off and the trans was in 3rd... manually shifted to 2nd and limped back to the house...

Put the scanner on it... 1 code... P0758 2-3 Shift Solenoid B Circuit Malfunction

Checked the trans fuse and checked for power at the plug which checked out so I figured it was the 2-3 shift solenoid itself...

Dropped the pan, replaced all the shift solenoids and serviced the trans. Once back together, cleared the codes and within a block the light was back on...

Next thought was wiring issue.... Started by pulling the ECU and unhooking the trans connector... Checked for continuity between the ecu and the trans plug (pins that control the shift solenoids) which checked out... Then dropped the trans pan again and checked for continuity between the shift solenoid connectors to the ecu... which also checked out fine...

Manually tested the new solenoids with 12v source and they function fine... as do the ones I removed that where "bad"

So... reinstalled the trans pan with another fresh filter and another 5qts of fresh fluid... re installed the ecu, (battery was unhooked for 5ish hours...) Started the truck, in drive with no CEL, trans is in 3rd... manually put it in 2nd.. it will go into 2nd... (limp mode).. drive for a block or so and the CEL came back on.. same code P0758

So... is it the trans or the ecu?

Anyone have this problem before??

Please help
-Chris

performabuilt

iTrader: (25)

Well since you seem to have covered the other things I would think maybe PCM or chasis ground.

AcIdBuRn02ZTS

Well... I'll have access to a GM Tech2 tonight so I plan on trying to shift the trans manually with it to see what happens...

What really confuses me is when I was finished checking all of this, I hooked up my Snapon Soulus Pro scanner... went into the trans diagnostics and was viewing the trans in real time...

When in drive... no cel on yet... the scanner was showing the trans to be in 1st gear however when you try to move, its obvious the truck was in 3rd... manually shift to 2nd and the scanner would see that... the truck would drop into 2nd and move... back to drive and the scanner would show 3rd gear and then the cel would light up...

I'm lost... ECU has been ordered but just wanted to make sure ive covered everything..

Thanks again
-Chris

AcIdBuRn02ZTS

Hooked up the Tech2... reset the cel...

In the trans controls, it was showing the ecu calling for 1st gear but the trans was still in 3rd... It shows both solenoids being on and the trans being in first but go to move and its def. in 3rd...

So... since the wiring and solenoids all tested good... I'm guessing the signal is being lost between the processor and the pin on the ecu itself... I'm kinda curious... we had NASTY storms the night before this happend... Could lightning have caused the issue? Just kinda odd that it suddenly has a problem after one of the worst storms we've had this year...

Anyways, ordered a new ecu... It'll be ready in the morning so we'll see...

If anyone else has any other ideas... please chime in.

Thanks
-Chris

AcIdBuRn02ZTS

Alright transmission gurus... I'm needing help...

Replaced ecu... cel is off... has 2nd, 3rd, and 4th... when in drive, the scanner shows being in 1st gear and both solenoids on.. however the truck is still in 3rd as if the 2-3 solenoid is still off...

NO cel codes thrown in the hour I drove it around... when I got back to the house, put the truck in park and it died instantly... then the cluster went haywire.. truck would crank but wouldnt start... wiggled the ign key a bit and it went back to normal...

CEL lit up saying lost contact with ecu I'm guessing when it died...

its NEVER had an issue with the ign. switch... never acted up... so why when I wiggled the switch did the truck start and act fine besides still not having 1st gear...

Another oddity... Ive got 2nd 3rd and overdrive....

Solenoids are like this...

1st gear - both on
2nd gear - Sol. A on Sol. B off
3rd gear - both off
4th gear - Sol. B on

So... both solenoids are working appartenly otherwise I would lose more then one gear... so it this a valve body problem or wtf?

I'm really confused and po'd at this moment...

Any ideas??
-Chris

AcIdBuRn02ZTS

Ok... I read that over and it sounded really confusing... so let me try and reword it a bit....

After replacing the ecu... start the truck and go to take off...

In drive, the scanner is showing the trans being in 1st gear with both solenoids being on... however when you actually try to take off... It feels like its in 3rd gear just like before...

Manually shift it to 2nd... scanner shows 2nd... shift it to 1st... scanner shows first... however when you try to move in 2nd or 1st... it feels like the truck is in 2nd gear... there is no difference between the two...

Take it out on the road... start with manually in 1st... scanner showing trans in 1st... take off (truck feels like its in 2nd... not 1st)... manually shift to 2nd (scanner shows 2nd) and you can feel a clunk but its not a shift... rpms dont drop... shift to 3rd... scanner shows 3rd... shift to drive and scanner shows dropping into 4th and you can feel the shift...

Dont know if the converter clutch is locking up... didnt want to get it up to highway speeds with it acting like it is...

After doing some reading... its kinda sounding like the 1-2 acc. piston has cracked.... Is this just a coincidence or did driving it while acting up cause it?

Please help if you can.

Thanks guys
-Chris

AcIdBuRn02ZTS

bump... anyone?

performabuilt

iTrader: (25)

I would lean to a bad ignition switch. I have run into that before.

performabuilt

iTrader: (25)

Also the 1-2 accum cracked will cause a second gear start but the other gears will be fine.

AcIdBuRn02ZTS

So... a bad ign. switch would cause the loss of 1st gear and no codes or other gear problems? Ive got 2nd, 3rd, and OD now... just no 1st and no codes with a 3rd gear start...

It seems that everything electronic is calling for 1st but the trans wont actually shift into 1st gear...

-Chris

performabuilt

iTrader: (25)

Then I would have to look at the 1-2 accum

552ndseries

I am on the same road with 05 escalade changed lower harness just in case as well cel comes on at 4th gear
what was your problem

rangooner

I have that code p0758 In a 98 sonoma I change all of the sshift solenoid and put in a valve body shift kit the shift kit does is job now I have 1st 2nd and 3rd gear but I have to manually shift it it won't shift itself it only stays in 3rd gear and no overdrive I'm going crazy I'm thinking of taking it to the dealership but I don't wanna pay hehehe arm and a leg for something I fix the transmission shops & Electrical shops around here why I'm working at in Louisiana don't want to mess with it for some reason please I seen your post that it could be a ignition switch if this had happened to you please reply to me as soon as possible appreciate it and take ur comments very handy thank you

performabuilt

iTrader: (25)

To determine is ignition switch you would need to USE a VOM to monitor the voltage to pin E or actually the wire that feeds it . It should be at B+ line 12 volts or higher generally running should be around 13.8 volts.
Frank

00keeganws6

Did anyone come up with the solution for the problem here??

mrvedit

I see you started your own thread "4L60E limp mode help!!!". That is good because your problem/symptoms are likely not exactly the same. Also no one wants to read this entire old thread.

Lets keep this thread closed unless the OP wants to re-open it.