Codes P0740, P0753, P0785, P1860?

Tiny
EARL91
  • MEMBER
  • 2000 CHEVROLET TAHOE
  • 180,000 MILES
I have the vehicle listed above Z71 5.7L. Codes P0740, p0753, p0785, p1860. It has a transmission in it that was refurbished 2 years ago. I installed a new create motor about a month ago. I check shift solenoid A and B. Both are working and receiving between 20 and 25 olm's about 21.7 to be exact. What are some things I can do to fix? Working on a budget.
Tuesday, April 25th, 2023 AT 4:31 PM

21 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Here is information on the codes:

P0740: Torque Converter Clutch Circuit Malfunction.

P0753: Shift Solenoid A Electrical Malfunction.

P0785: Shift/Timing Solenoid Malfunction.

P1860: TCC PWM Solenoid Circuit Electrical Malfunction.

I would start by checking the electrical connector at the transmission. If that looks okay, I would install a rebuilt valve body. Check out the images (below). Please let us know what happens. Also, how is the fluid condition, is it burnt or low?
Images (Click to make bigger)
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Thursday, April 27th, 2023 AT 10:17 AM
Tiny
EARL91
  • MEMBER
  • 89 POSTS
The fluid is good. I dropped the pain and checked the shift solenoids, and they were good. I cleaned everything while I was there. Changed the filter and put new fluid in. Do you think putting a new harness in would fix my problem? I have done a little research and it seems that that could possibly fix it.
Was this
answer
helpful?
Yes
No
Friday, April 28th, 2023 AT 6:30 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yes, if the wiring is bad, it will cause this problem. Here is a guide to help you test the wiring with the transmission wiring diagrams below:

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
Was this
answer
helpful?
Yes
No
Saturday, April 29th, 2023 AT 11:21 AM
Tiny
EARL91
  • MEMBER
  • 89 POSTS
The valves in the valve body moved easily. So, I don't think it's that. That why I asked about harness. Thank you for the info. I will let you know how it goes.
Was this
answer
helpful?
Yes
No
Sunday, April 30th, 2023 AT 7:49 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Please do, have a great day.
Was this
answer
helpful?
Yes
No
Sunday, April 30th, 2023 AT 10:52 AM
Tiny
EARL91
  • MEMBER
  • 89 POSTS
I replaced the harness in the transmission. The truck can move better. I don't have to almost floor it to move. But the codes are still there after clearing them with the scanner. Also still can't feel or hear the truck shift. What would the next step be?
Was this
answer
helpful?
Yes
No
Friday, May 12th, 2023 AT 10:56 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
I would install a rebuilt valve body, or you could have a bad PCM. How is the fluid condition?

This guide can help:

https://www.2carpros.com/articles/how-to-check-and-add-transmission-fluid

Please go over this guide and get back to us.

Was this
answer
helpful?
Yes
No
Saturday, May 13th, 2023 AT 10:05 AM
Tiny
EARL91
  • MEMBER
  • 89 POSTS
Can a bad ignition switch cause these shifting problems? My tachometer and speedometer on my cluster stopped working. And then all these problems started.
Was this
answer
helpful?
Yes
No
Thursday, May 18th, 2023 AT 5:36 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yes, it could, here is how to change the switch out in the images below. Check out the images (below). Please let us know what happens.
Images (Click to make bigger)
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Thursday, May 18th, 2023 AT 12:25 PM
Tiny
EARL91
  • MEMBER
  • 89 POSTS
Ignition switch did not.
Was this
answer
helpful?
Yes
No
Sunday, May 28th, 2023 AT 8:57 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
It seems like it is the valve body or the wiring, did all of these codes come in only after you changed the transmission out?
Was this
answer
helpful?
Yes
No
Tuesday, May 30th, 2023 AT 9:20 AM
Tiny
EARL91
  • MEMBER
  • 89 POSTS
Okay. So, I bought this truck. The motor was locked up. It blew the cylinder walls out. So, I put a new motor in. The transmission was rebuilt about two years ago. It was all running good for about two weeks then all of the codes appeared. I have changed the internal harness. All new solenoids, new filter. And ignition switch. The only thing I haven't changed is the valve body and pump.
Was this
answer
helpful?
Yes
No
Thursday, June 1st, 2023 AT 5:40 AM
Tiny
EARL91
  • MEMBER
  • 89 POSTS
I'm also going to check my converter make sure it's not loose.
Was this
answer
helpful?
Yes
No
Thursday, June 1st, 2023 AT 5:41 AM
Tiny
EARL91
  • MEMBER
  • 89 POSTS
Any way you could send me all wiring diagrams for my transmission?
Was this
answer
helpful?
Yes
No
Thursday, June 1st, 2023 AT 8:41 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
They are in the post above, click to enlarge in the images.
Was this
answer
helpful?
Yes
No
Friday, June 2nd, 2023 AT 8:19 AM
Tiny
EARL91
  • MEMBER
  • 89 POSTS
Could the gauge cluster not working cause my no shift issue?
Was this
answer
helpful?
Yes
No
Thursday, July 13th, 2023 AT 1:41 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
So, the speedometer is not working? If so, this can be the problem, I would swap out the VSS sensor. Check out the images (below). Please let us know how it goes.
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Friday, July 14th, 2023 AT 8:57 AM
Tiny
CHRIS MORGAN4
  • MEMBER
  • 2 POSTS
I know this is an old post but did you ever find a solution? I have a 02 Escalade with the exact symptoms.
Was this
answer
helpful?
Yes
No
-1
Tuesday, October 15th, 2024 AT 7:37 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Good question, I just spoke with EARL91 so he should respond. I think the transmission needed to be rebuilt.
Was this
answer
helpful?
Yes
No
Wednesday, October 16th, 2024 AT 10:39 AM
Tiny
EARL91
  • MEMBER
  • 89 POSTS
The gauge cluster being replaced did fix my issue.
Was this
answer
helpful?
Yes
No
Friday, October 25th, 2024 AT 4:50 PM

Please login or register to post a reply.