Multiple tranny codes and fuse 47 issues

[Mcgrath88]

I bought a trailblazer needing a tranny and i replaced it. It has multiple solinoid codes. I have power at both sides of fuse 47. I have power at the plug on the tranny. The codes show as soon as i start it even if i erase them. When i shift out of park it immediately blows fuse 47. If i unplug the tranny it doesnt blow the fuse. Am i supposed to have 12v to pins E,C,P,R and i have 5v to pin L? I pulled all the wire loom off the harness up to the starter and inspected the wires. Found no issues there either.

I dropped the pan and pulled the internal harness and couldnt find any broken or worn wires. All of the solinoids were in ohm specs. Fluid was dirty with very fine metal bits but not the worst ive seen.

Anybody have a clue whats going on? It also has a remote starter installed and i do not have the fobs for it.

Codes are:
P0740
P0753
P0758
P0785
P1860

 

[Sparky]

Maybe try undoing the remote starter stuff as a starting point (no pun intended) , since you can't use it anyway.

 

[Mcgrath88]

Im about to do that next. Gonna put the harness back in and the solinoids and some new fluid now and go from there. I have another pcm also. Should i try swapping that if removing the remote starter doesnt do it?

 

[Mcgrath88]

Just pulled the remote starter. Didnt help. Swapped the pcm and did the security relearn. Still have codes and still blowing that fuse. Anybody have a clue what to try next?

 

[Mooseman]

You would need to ohm each wire and check that none that aren't supposed to short to ground. Check my signature for the link to the manuals with the schematics.

 

[Mcgrath88]

You would need to ohm each wire and check that none that aren't supposed to short to ground. Check my signature for the link to the manuals with the schematics.

The wires inside the tranny or outside? Could a solinoid still be bad and ohm in spec? Its weird it only blows the fuse when i pull it out of park. But the codes come up before it blows that fuse.

 

[Mooseman]

I'd do both. Probably when the PCM tries to energize a solenoid, that's when it blows the fuse, which would make sense. I'd check both inside and outside the tranny.

For some reading:

Multiple transmission codes

My cars been running incredible since I've got it but the other morning I come out and try to take off and Ive got no power run a diagnostic and have 5 codes pop up at once p0740 torque converter clutch circuit open p0753 shift solenoid a P0758 shift solenoid b P0785 shift timing solenoid P1860...

gmtnation.com

 

[Mcgrath88]

I'd do both. Probably when the PCM tries to energize a solenoid, that's when it blows the fuse, which would make sense. I'd check both inside and outside the tranny.

Ok thanks ill mess with that. Can you confirm that the pins i have power at are correct?

Also how do i get to these schematics you have?

 

[Mooseman]

Need GMT360/370 Service Manuals? Get them Here!

 

[Mcgrath88]

So i figured out the code and fuse issue. When i replaced the tranny i had to change the neutral safety switch plug. Well that plug has two yellow wires and i guess i had them reversed. I switched them and now it shifts. I have a separate issue now and i think 3rd is gone in the tranny. Shifting from 2nd to 3rd in just revs out. Probably explains the fine metal in the fluid.

 

[Mooseman]

Thanks for reporting back. I suppose it was a used tranny you put in if you had to rig the neutral switch plug.

 

[Mcgrath88]

Thanks for reporting back. I suppose it was a used tranny you put in if you had to rig the neutral switch plug.

My trailblazer is a 03 and the doner was a 04. They had different plugs on them. 04 had one plug and 03 had two plugs.

 

[Paul Bell]

Hello folks, I'm having this problem. The truck is stuck in third gear with all these transmission codes reporting.

I downloaded the diagrams (Thanks Moosman!!) and it does NOT have 2003 wiring diagrams. I'll assume the 2004 wiring is the same? I know the internal transmission harness & plug is the same from 03 to 04.

It appears that I have good power at fuse 47 with the ignition on.

Any hints what to look at next?

Thanks!

 

[Mooseman]

The ground wire? Check for power at the tranny plug. Multiple codes is usually a result a wiring issue, either outside or inside the tranny.

 

[Paul Bell]

Thanks for the response.

I screwed up, I do NOT have power at the fuse. The fuse was good but no power with the key on.

Looks like I have a bad ignition switch.

Until I install the new switch, I backfed fuse 47 from another switched fuse with a wire jumper and the transmission works fine, codes stay off.

Whew!!