SPONSORED LINKS

Codes of P0740, P0758 and P1860, poor shifting and slipping?

Tiny
CRYPTOKING
  • MEMBER
  • 2005 CHEVROLET SILVERADO
  • 6.0L
  • V8
  • 2WD
  • AUTOMATIC
  • 65,000 MILES
Did engine swap to 6.0l using 4l60e transmission. Did re-pin on harness using this guide: https://youtu.be/vZDXET1w1PY?si=SbLrY0crAHPXavOy. Have poor shifting, slipping and codes. Check connector and harness twice. Everything looks right. Perplexed. Please help.
SPONSORED LINKS
Monday, March 4th, 2024 AT 6:48 AM

12 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,245 POSTS
I would double check the pin location. also, did you swap the PCM and complete wiring harness? Here is how the transmission should be wired. Here is a guide so you can check the wiring connections:

https://www.2carpros.com/articles/how-to-check-wiring

Check out the images (below). Please let us know what happens.
Images (Click to make bigger)
Thumb
Thumb
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Monday, March 4th, 2024 AT 11:01 AM
Tiny
CRYPTOKING
  • MEMBER
  • 27 POSTS
I checked the wiring and completed the wiring to the ECM. I did not swap out PCM. Is that inside the transmission?
Was this
answer
helpful?
Yes
No
Monday, March 4th, 2024 AT 11:23 AM
Tiny
CRYPTOKING
  • MEMBER
  • 27 POSTS
Could there also be a mismatch of flex plate to converter? I did have to change out flywheel and remove spacer to ensure that the starter would match up.
Was this
answer
helpful?
Yes
No
Monday, March 4th, 2024 AT 11:24 AM
Tiny
CRYPTOKING
  • MEMBER
  • 27 POSTS
Codes are 740, 758 and 1860.
Was this
answer
helpful?
Yes
No
Monday, March 4th, 2024 AT 11:25 AM
Tiny
CRYPTOKING
  • MEMBER
  • 27 POSTS
The ECM was refreshed to the 6.0l. Also has a stage 1 cam.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Monday, March 4th, 2024 AT 11:31 AM
Tiny
CRYPTOKING
  • MEMBER
  • 27 POSTS
The PCM is the same from the 4l60 just reminded at pins 42 and 79.
Was this
answer
helpful?
Yes
No
Monday, March 4th, 2024 AT 11:42 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,245 POSTS
Sorry its Monday! You included the codes my bad. Yes, the PCM is located next to the radiator.

P0740 - Torque Converter Clutch Circuit Malfunction:

P0758 - Shift Solenoid 'B' Electrical:

P1860 - TCC PWM Solenoid Circuit Electrical

So, the wiring looks like it might be incorrect. I would remove the transmission electrical connector so you can match the colors the wires going into and out of the main transmission connector. Here is the location of the PCM. Check out the images (below). Let us know what you find.
Images (Click to make bigger)
Thumb
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Monday, March 4th, 2024 AT 11:53 AM
Tiny
CRYPTOKING
  • MEMBER
  • 27 POSTS
So, I did check out the wires yesterday at the tranny. Moved original pin S to U. Created new S pin to ECM pin 79 and new T pin to ECM pin 42.
Was this
answer
helpful?
Yes
No
Monday, March 4th, 2024 AT 12:10 PM
Tiny
CRYPTOKING
  • MEMBER
  • 27 POSTS
That's how I wired it. Is that wrong?
Was this
answer
helpful?
Yes
No
Monday, March 4th, 2024 AT 12:11 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,245 POSTS
I am not sure how you wired it, I would double check the colors going into, and out of the main connector to make sure it matches the wiring diagrams I provided. Can I ask why you repinned it in the first place?
Was this
answer
helpful?
Yes
No
Monday, March 4th, 2024 AT 12:16 PM
Tiny
CRYPTOKING
  • MEMBER
  • 27 POSTS
The harness is from the 6.0l and the transmission is a 4l60. Had to do the re pin from what I was told.
Was this
answer
helpful?
Yes
No
Monday, March 4th, 2024 AT 12:19 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,245 POSTS
I would try putting it back to the way it was.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Tuesday, March 5th, 2024 AT 9:41 AM

Please login or register to post a reply.

Related P0758 Content

VIEW MORE

Sponsored links