phirepower

iTrader: (2)

My friend's car is throwing a p1870, manufacturer contrl transmission...


causes

i'm told it is most likely 1 of 3 issues. none of which i know how to do. They are

1 restricted PWM solenoid screen
2 worn converter lock up clutch
3 worn converter regulator valve

I drove the car today, it feels like it shifts ok, no shakes or obvious slipping... anyone else have an idea? if not, can anyone outline how to check any of the listed potential problems?

the car is 1998 cavalier, automatic, with nearly 130,000

Any advice would be appreciated, Thanks, Dan

Tonner

Possibility any of the above imo.


Thats a code I hate to see, but in my case 04 4l65e,, with failed converter lockup usually.


I just got it come up in a different car yesterday after fitting a non lockup Hi stall converter.
We forgot to disable lockup via the pcm.



Here is a bit of info I found once about the code.

"" Motor, Jun 2006 by Colonna, Wayne
The newest transmission technology provides nearly unnoticeable torque converter clutch application. As is often the case, an appreciation of how it works will help you understand why if something goes wrong.

Diagnostic trouble code P1870 (Transmission Component Slippage) is a General Motors-specific code whose set parameters are determined by transmission type and engine size. The PCM monitors and compares engine speed to vehicle speed after the converter clutch has been commanded ON in either high gear or Overdrive. Should the expected rpm ratio exceed predetermined parameters, DTC 1870 sets. And upon doing so, the PCM elevates the transmission main line pressure and stops converter clutch apply.


In some instances, the PCM also will inhibit 4th gear and may or may not illuminate the MIL. This really is an added safety strategy, as the PCM had already monitored the upshifts and determined all was well through those ranges. Once the vehicle has made it to a cruise state, the PCM then begins to monitor the vehicle's cruise ratio. If at some point the transmission begins to slip, P1870 sets and line pressure is elevated in an attempt to stop any further slippage and prevent further damage. This would explain why DTC 1870 Ls often accompanied by a complaint of a hard 1-2 upshift.




EDIT: did you find the cause?

mike13

iTrader: (27)

P1870 is usually a worn valve bore in the valve body, a very common problem with GM trans. Do a google search or contact any trans shop and they'll have a fix. You can buy a rebuilt valve body with the bore drilled and sleeved. Or they do that to your valve body.

performabuilt

iTrader: (25)

I can give you and easy fix shoot me a PM

Trenton Bundy

what’s this easy fix for the p1870 code?

MaroonMonsterLS1

Are you kidding me?
I see you are new to the forum. Joined today and this is your first post.
Here is a pointer, look on the left side of the posts and see the date they were posted.

You just responded and brought back from the dead a 13+ year old post
Start your own post coverinig your own issues and you will get the best response

If you want a generic answer, flipping the inner TCC reg valve, meaning putting just the inner part of the valve in backwards, will usually cure 1870 codes
If you are dont understand that, then just buy a Fitzall brand TCC valve and install it.
probably 80% of the time it will make the code go away and extend the life of the trans, but often the damage is already done to the tq converter and it's a matter of time before the worn lining actually just fails

antoine

just drop the valvebody and take the tcc isolator valve out and just flip it.

vorteciroc

UuuuuuggGGgggghhhhHh!

mrvedit

Nuff said. Thread closed. If there were a way to close all old threads, I would do it.