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P1870 present with "Transgo Fix"

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Old Apr 1, 2024 | 11:27 PM
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Default P1870 present with "Transgo Fix"

I can't seem to find any threads that have the P1870 code after a transgo PWM eliminator valve was installed. It's a somewhat new rebuild 3,000 miles or so. No problems except lock up doesn't work and it has high line pressure currently (280ish).

It's Dana's kit from probuilt that was assembled by me. I did new AcDelco electriconics when rebuilt. It has a 9.5 converter from edge racing. How do I determine if it's the converter? Is the trango valve a sure long lasting fix?

Any guidance is appreciated.
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Old Apr 11, 2024 | 12:15 PM
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Did you replace the harness inside the transmission? If not, did you replace the TCC solenoid, the one the is hardwired to the harness? Have you checked the TCC solenoid ohms? If you apply power to the solenoid, can you hear it click?
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Old Apr 11, 2024 | 05:56 PM
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1870 is cause by pcm commanding the converter to lock and its not locking. You need a scanner with bi directional controls to really figure out what it's doing.
If you tore or forgot to put the oring on the snout of the input shaft that will cause it too.

I've used the pwm eliminator kit for years on mine and customers it never wears out so there is something else.

What is the background leading up to your deciding to install the kit.
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Old Apr 14, 2024 | 11:43 AM
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This is best moved to the Automatic Transmission section, which I am doing now.
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Old Apr 14, 2024 | 12:01 PM
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TG valve could be stuck , Oring damaged or missing on shaft, TCC valve or solenoid stuck or bad, Or converter. Even blocked orifice in converter feed to soleiond by a small peice of trash or something. You need to look at data to really determine whats what.
280ISH line IMO is way high unless you are measuring it in reverse even with 1870 code max line.
But basically P1870 means converter commanded to lock, lockup did not occur.
Had lockup been working since build ? if so i would go to solenoid first. But I would also want to understand why line is at 280 max if happening in D as that would also be close to your max line at WOT which to me is a bit high.
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Old Apr 15, 2024 | 06:43 PM
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If this was self installed. The VB gaskets could be in the wrong place causing the high line pressure. The TransGo valve could be installed backwards causing the TCC slip. P1870 is a slip code, here is a PDF on the code. I have fixed many 4L60E's with a P1870 code by installing the TransGo TCC regulator valve and nothing else...
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File Type: pdf
ATRA P1870 Diagnostic.pdf (872.5 KB, 136 views)
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