What is code P1870?
Melting Slicks
Joined: Nov 2003
Posts: 3,011
Likes: 9
From: Dublin GA
Whenever you install a high stall converter, you will have to let the tuner know so he can change the parimeters on the sensor tables. I had mine changed but for some reason I am still getting it on occasion. You will need to reset this code each time you get it until you get the problem resolved. It wil cause the 1-2 shift to be extremly hard.
Drifting
Joined: Oct 2003
Posts: 1,540
Likes: 0
From: bloomfield nj
Originally Posted by DJMRTS
I had no errors for two years now with the new TC. This code popped up about 350 miles after I went to 3:42 from 3:15 gears. So a good tuner guy can resolve this?
after the 3.42 install,i'm assuming you had the shift points recalibrated.if the tranny is beginning to slip shift/engine flare during a shift,etc.i would tend to think the tranny is going into death mode.if it was from the gear swap it should've started immediately,not after 300 miles.JMO
Last edited by dpd; Feb 19, 2006 at 05:05 PM.
Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
if it was from the gear swap it should've started immediately,not after 300 miles.JMO
The only way for an aftermarket TC to cause a P1870 error code is if the lock-up clutch mechanism is faulty.
Assuming the new higher stall TC's TCC is not faulty, then the only other thing left to set the P1870 is the gear ratio change.
Quote from the tech manual:
The powertrain control module (PCM) monitors the difference between engine speed and transmission output speed. In D3 drive range with the TCC engaged, the engine speed should closely match the transmission output speed. In D4 drive range, with the TCC engaged, the TCC slip speed should be -20 to +50 RPM.
When the PCM detects excessive TCC slip when the TCC should be engaged, then DTC P1870 sets. DTC P1870 is a type B DTC.
Conditions for Setting the DTC
DTC P1870 sets if the following conditions occur for three TCC cycles.
The TCC is commanded ON for 5 seconds.
The TCC is at 40 percent duty cycle for 5 seconds.
The TCC slip speed is 130-800 RPM for 7 seconds.
Important
The following actions may occur before the DTC sets.
If the TCC is commanded ON for 5 seconds, the TCC is at 40 percent duty cycle for 5 seconds, the TP angle is 20-99 percent and the transmission slip counter has incremented to either 1 or 2, out of 3 to increment the fail counter for the current ignition cycle, then the following slip conditions and actions may increment the fail counter for the current ignition cycle: These conditions must occur sequentially.
Condition 1
If the TCC slip speed is 130-800 RPM for 7 seconds, then the PCM will command maximum line pressure and freeze shift adapts from being updated.
Condition 2
If Condition 1 is met and the TCC slip speed is 130-800 RPM for 7 seconds, then the PCM will command the TCC Off for 1.5 seconds.
Condition 3
If Condition 2 is met and the TCC slip speed is 130-800 RPM for 7 seconds, then the fail counter on the current ignition cycle is incremented.
The above slip conditions and actions may be disregarded if the TCC is commanded OFF at any time as a result of a driving maneuver, sudden acceleration or deceleration.
Action Taken When the DTC Sets
The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
The PCM commands maximum line pressure.
The PCM inhibits TCC engagement.
The PCM inhibits 4th gear if the transmission is in hot mode.
The PCM freezes transmission adapt functions.
The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
The PCM stores DTC P1870 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.
Conditions for Clearing the MIL/DTC
The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
A scan tool can clear the MIL/DTC.
The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.
Last edited by Mike Mercury; Feb 19, 2006 at 11:14 PM.
Thread Starter
Burning Brakes
Joined: Mar 2003
Posts: 874
Likes: 0
From: Bonita CA
Hi Guys, thanks for the very informative input. Have not yet had a tune after the gear change. I plan to get it done soon and hopfully that the code(s) will not come back. Thanks
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