Stuck after valve body repair S.O.S

[BrooklynBay]

Check the PCM ground wire connector for corrosion.

 

[TheJerm]

not yet

Check the PCM ground wire connector for corrosion.

Checked the ground cleaned it all up and still nothing. I guess maybe it's time to see if I can afford a new VB, unless there is a sure-fire test to tell if the PCM is bad. I've been stuck for close to two weeks. besides a pressure test, because I can't get anywhere, is there any other test you know of that might pinpoint this?

 

[BrooklynBay]

You said that the PCM circuit had excessive resistance, so a different valve body won't help if that is the issue. Back tracking to a previous post, you said that the internal wiring harness in the transmission was good but the wiring from the PCM connector to the transmission had excessive resistance on a few wires (around 75 Ohms). I assume that you checked each wire from the PCM connector to the main bulkhead connector on the transmission (or at the solenoids inside the transmission).

 

[TheJerm]

FPR is the resistance!

You said that the PCM circuit had excessive resistance, so a different valve body won't help if that is the issue. Back tracking to a previous post, you said that the internal wiring harness in the transmission was good but the wiring from the PCM connector to the transmission had excessive resistance on a few wires (around 75 Ohms). I assume that you checked each wire from the PCM connector to the main bulkhead connector on the transmission (or at the solenoids inside the transmission).

yeah, I checked all of the wires extensively, while following them with a wiring diagram I noticed that the #80 light blue/orange wire from the PCM, the wire with the resistance, its first stop is the Fuel Pump Relay. The whole circuit starts there! I then pulled the FPR off and tested it... voila 75 ohms, pulled off the other relays in the power junction box. same thing they all have a resistance of 75 ohms when there is no power to the relay. so it is not a bad wire. I checked the entire ground system from a diagram. found one bad body ground by the driver side back door. replaced it, no dice. literally, if I go one by one and figure out which wire has to be disconnected at the trans for reverse to work, I could put a switch on it, a rheostat on the EPC wire and just get down the road with my new style hybrid automatic/manual trans. I am an electrician btw, so wiring is my thing. so the question I have to figure out now is: exactly what series of events take place in the VB to cause a transmission to go into reverse? and then work backwards from there. right now it's: electricity to trans = no reverse no drive, no electricity to trans = reverse and first. I'm leaning toward something sticking or leaking in the VB. I'm heading out to mess with it again. I will be sure and update. a big thank you for all of your help so far. and not just on this post, you've helped me a hundred times already and you didn't even know it.

 

[BrooklynBay]

I saw a recent post about somebody which had a no drive or reverse situation, and wanted to rule out the possibility of an electrical issue. He unplugged the main bulkhead connector, and the transmission had drive & reverse gears. He lost these gears when he plugged the connector back in. Try this then get back to me.

 

[TheJerm]

I saw a recent post about somebody which had a no drive or reverse situation, and wanted to rule out the possibility of an electrical issue. He unplugged the main bulkhead connector, and the transmission had drive & reverse gears. He lost these gears when he plugged the connector back in. Try this then get back to me.

same thing, if it's connected no reverse no drive, if it's not connected I have reverse and first

 

[BrooklynBay]

I thought that I saw it posted in another thread. Looking back at post number 26 in this thread I saw that you posted it.

 

[TheJerm]

I thought that I saw it posted in another thread. Looking back at post number 26 in this thread I saw that you posted it.

seems like that would be a pretty big clue, but without knowing what exactly goes on in the VB, I cant interpret it. that quote said it could not be an electrical problem, so it is either a bad pcm or bad wiring. the wiring is confirmed good from the solenoids to the pcm. is there a test to see if a computer is bad? I have reset it probably ten times in the last ten days so maybe I screwed it up.

 

[BrooklynBay]

A transmission shop has a special scanner (or should have) to simulate driving conditions while the vehicle is not in motion. It will cycle the shift solenoids, vary the EPC pressure, and vary the TCC apply rate.

 

[TheJerm]

A transmission shop has a special scanner (or should have) to simulate driving conditions while the vehicle is not in motion. It will cycle the shift solenoids, vary the EPC pressure, and vary the TCC apply rate.

I wouldn't feel comfortable driving it that far like this, and with a tow and what they charge for the test and a tow home. I cant swing that + a repair. I guess I'm stuck. lesson learned, I should've just ignored the shift flare, everything else was perfect. I helped a buddy 6 months ago do the same exact thing and it went without a hitch. if it aint broke...

 

[BrooklynBay]

You could send the valve body out to be tested by Central Valve Bodies to rule that out.

 

[TheJerm]

You could send the valve body out to be tested by Central Valve Bodies to rule that out.

how much does that run? I just found a test I can try.

in reverse only SS1 is activated with TCS off.
in reverse SS1 and SS4 are activated with TCS on.

So will this work with just the key on? if I turn the key on ,turn off the O/D button and put it in reverse, I should get 12 volts only to SS1 right? anything else would show a problem.

 

[TheJerm]

SS1 symptoms

Improper gear selection depending on failure mode and manual lever position.
Failed ON: No 4th and 5th
Failed off: No 1st and 2nd

 

[BrooklynBay]

This is where that scanner would come in handy. It will automatically simulate these tests.

 

[TheJerm]

This is where that scanner would come in handy. It will automatically simulate these tests.

boy I wish I had one, this 5r55e manual is awesome. it shows what happens when every solenoid fails open or closed, never mentions the word reverse once!

 

[BrooklynBay]

Check WWW.ATRA.Com for a local shop. Maybe they have one close by.

 

[BrooklynBay]

This link has information on using a scanner to test shift solenoids, PCM driver output to the solenoids, and explains how a bad shift solenoid could cause a shift flare: http://transtechdiag.com/gmdiagnosticinfo.html

 

[TheJerm]

new clue maybe.

Check WWW.ATRA.Com for a local shop. Maybe they have one close by.

I pulled off the harness on the tranny. turned the key on and checked the voltage in park and reverse.

with key turned on in park all four solenoids are receiving 11.4v, TCC 11.4v, EPC 10.6v

in reverse all the same except EPC 10.3v

now in park the only solenoid supposed to be working is SS1, and in reverse with the O/D off only SS1 should work, O/D on and SS4 should work too. could this signal a computer or sensor problem, or does the car have to be running to do this test.

 

[BrooklynBay]

The PCM receives a signal from the VSS when it's in motion. The transmission also has internal speed sensors on certain models. These sensors tell the PCM when to shift to another gear ratio. A scanner will simulate the vehicle in motion even though it's not moving.

 

[TheJerm]

The PCM receives a signal from the VSS when it's in motion. The transmission also has internal speed sensors on certain models. These sensors tell the PCM when to shift to another gear ratio. A scanner will simulate the vehicle in motion even though it's not moving.

if a shift solenoid is receiving 12v does that mean it is on? if so that is a problem because all of them are on. only SS1 is supposed to be on in park!


also, at the transmission bulkhead for the TSS sensor I have 72 ohms, is that normal? and isn't this the little clip that goes into the inner harness on VB?