P1870 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat
GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat

Go Back   GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat > Pontiac Bonneville > OBD-II Trouble Shooting

OBD-II Trouble Shooting Got a code reader? Find out what your GM car's Check Engine light is trying to tell you (and then turn Check Engine light off).

LinkBack Thread Tools Search this Thread
Old 02-02-2010, 01:13 AM   #1
Senior Member
True Car Nut
Purplehazeir's Avatar
Join Date: Sep 2008
Location: Arlington, WA
Posts: 7,979
Thanks: 0
Thanked 1 Time in 1 Post
Purplehazeir is on a distinguished road
Default P1870


Typically, these vehicles will have been driven more than 32,000 km (20,000 mi) before this condition occurs.

The scan tool may show a DTC P1870 set as a history code.
A harsh 1-2 shift or DTC P1870, caused by wear in the control valve body, may be difficult to duplicate when the transmission temperature is below 93C (200F).


The condition may be due to wear in the control valve body. This wear occurs in the bore that contains the TCC isolator and regulator valves, and results in poor, or no, TCC apply


DTC P1870 is a type B code. The conditions for setting the P1870 DTC must occur on TWO CONSECUTIVE TRIPS (ignition cycles, with a drive cycle) before setting a P1870 history code.

When the conditions for setting DTC P1870 are met (first trip), the PCM commands maximum line pressure and harsh 1-2 shifts are the result.
This may result in a harsh 1-2 shift with no history code if the conditions for setting the DTC required for the second trip are not met, on two consecutive trips (Ignition cycles, with a drive cycle).

When the conditions for setting the DTC are met, on the second consecutive trip, a DTC P1870 is stored as a history code.
When the P1870 code is stored, the PCM will turn on the Service Engine Soon (SES), Check Engine Light (CEL), or Malfunction Indicator Lamp (MIL).


Install a control valve body with the revised TCC regulator and isolator valves. These valves are used in all transmissions produced after January 15, 1999 (Julian Date 9015), and all of the service parts currently available through GMSPO contain revised TCC regulator and isolator valves.


If all of the following conditions are true, it is not necessary to rebuild the transmission or to replace additional transmission components beyond the control valve body.

Transmission operation is normal before the transmission reaches operating temperature, or before DTC P1870 is set (no slips, flares, or missing gears).
The torque converter is not blue or overheated.
The transmission fluid is not burned or has no burned odor.
The transmission fluid pan contains no abnormal debris (clutch material, bronze, brass, or metal fragments.
Purplehazeir is offline  

LinkBacks (?)
LinkBack to this Thread: http://www.gmforum.com/obd-ii-trouble-shooting-153/p1870-288046/
Posted By For Type Date
p1870 code buick This thread Refback 12-01-2015 10:50 AM
What is OBD 2 CODE P1870? This thread Refback 07-10-2013 05:46 AM

Similar Threads
Thread Thread Starter Forum Replies Last Post
4T65-E p1870 Sonnax repair kits CrimsonBane 1992-1999 2 06-21-2006 08:47 PM
Things always happen to me... P1870 code. alec_b 1992-1999 10 06-17-2006 04:21 PM
Code P1870...What does it mean??? macho_mike21 1992-1999 6 06-11-2005 02:44 PM
DTC P1870 (Transaxle Component Slipping (4T60-E Trans) throb 2000-2005 3 04-17-2003 01:48 PM
DTC P1870 (Transaxle Component Slipping (4T60-E Trans) throb 1992-1999 1 04-15-2003 07:49 PM

obd2, obdii, p1870

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 12:15 PM.