Gear swapped, Now getting this code ....
Thread Starter
Melting Slicks
Joined: Aug 2001
Posts: 2,735
Likes: 5
From: Tennessee
Gear swapped, Now getting this code ....
Got my rear end swapped from a 3.15 to a 3.42 and put a Yank 3000 torque converter in at that time. Got it tuned with LS-1 edit.....Now the problem, the check engine light is on with a P1870 code. I cleared the codes out and the P1870 came back...
What does this code mean and how do I get rid of it with the LS-1 edit ?
What does this code mean and how do I get rid of it with the LS-1 edit ?
Le Mans Master
Joined: Feb 2002
Posts: 5,407
Likes: 1
From: HONOLULU HAWAII
Re: Gear swapped, Now getting this code .... (Corvette Poor)
I am not sure but maybe with your aftermarket stall converter your computer is detecting slippage in your trannny...just a guess.
Melting Slicks
Joined: Oct 2002
Posts: 2,200
Likes: 0
Re: Gear swapped, Now getting this code .... (Corvette Poor)
Safety Car
Joined: Aug 2000
Posts: 4,154
Likes: 1
From: Murphy TX
Cruise-In II Veteran
Re: Gear swapped, Now getting this code .... (Corvette Poor)
I'm with Al and my bet too is, as usual, programming. I'd recommend using a scan tool to verify what your slip speeds look like. You see lots of posts saying you'll see this if you have a high stall converter but that's not correct. This test only runs when the converter is supposed to be locked and slip is minimal. I run my SY3500 with near (scaled) stock apply/release points and stock limits on this test (they can be raised to tolerate more slip w/o coding, you shouldn't need to do this IMO) and haven't thrown this code in over a year now.
Safety Car
Joined: Aug 2000
Posts: 4,154
Likes: 1
From: Murphy TX
Cruise-In II Veteran
Re: Gear swapped, Now getting this code .... (Corvette Poor)
I forgot to answer your question... :bb
The test attempts measure the difference between engine speed and transmission input shaft speed (or ISS) in order to assist in identifying failing mechanical components. (It's just the first step in fault isolation.) Since the ISS isn't measured directly, the PCM approximates it using the VSS signal and knowledge of tranny gear ratios, rear axle ratio, tire height, etc. Basically all the sources of slip between the engine and the transmission output shaft are lumped into the TCC Slip Speed parameter. The idea is to run the test when the contribution of the TCC is smallest, i.e. when it's locked. If the slip value looks too big, it codes. If your converter is having trouble locking or staying locked or the PCM's approximation of ISS is incorrect due to programming issues the test can fail easily. The test limits can be adjusted but you shouldn't need to (or want to IMHO) do this. They were added to LS1-Edit as a workaround while proper gear scaling was worked out.
The test attempts measure the difference between engine speed and transmission input shaft speed (or ISS) in order to assist in identifying failing mechanical components. (It's just the first step in fault isolation.) Since the ISS isn't measured directly, the PCM approximates it using the VSS signal and knowledge of tranny gear ratios, rear axle ratio, tire height, etc. Basically all the sources of slip between the engine and the transmission output shaft are lumped into the TCC Slip Speed parameter. The idea is to run the test when the contribution of the TCC is smallest, i.e. when it's locked. If the slip value looks too big, it codes. If your converter is having trouble locking or staying locked or the PCM's approximation of ISS is incorrect due to programming issues the test can fail easily. The test limits can be adjusted but you shouldn't need to (or want to IMHO) do this. They were added to LS1-Edit as a workaround while proper gear scaling was worked out.
Team Owner
Joined: Apr 2001
Posts: 54,204
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From: S.W. Ohio. . . . . . NRA Life Member
Re: Gear swapped, Now getting this code .... (ToplessTexan)
TT is dead on.
Plus, you can get the P1870 even though you would of kept the stock TC.
And the suggestion to first make sure your new TC is locking is the first thing I would check as well.
How soon after the swap did the P1870 code pop-up?
[Modified by Mike Mercury, 8:36 PM 8/24/2003]
Plus, you can get the P1870 even though you would of kept the stock TC.
And the suggestion to first make sure your new TC is locking is the first thing I would check as well.
How soon after the swap did the P1870 code pop-up?
[Modified by Mike Mercury, 8:36 PM 8/24/2003]
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