P1870 and Shifting Trouble
P1870 and Shifting Trouble My car is throwing a P1870 code and doing the following things...
1. I have noticed the change in feel and rpm when the converter locks-up os not as drastic as it used to be.
2. After a couple minutes of driving the 1-2, and 2-3 shift become deleyed and harsh, but the car acts fine when started and for the first couple of miles.
3. The shifting acting up is not constant, but I have a constant SES light on the P1870.
I have the stock A4 trannsmission in my 99 Z28, with an aftermarket Fuddle 3400 Converter I bought in December.
I did some research on this site and it seems my problem is either a tuning issue, or a bad Tourque Converter, which does not seem right as my TC is pretty new.
Any advice on how I should troubleshoot the problem?
1. I have noticed the change in feel and rpm when the converter locks-up os not as drastic as it used to be.
2. After a couple minutes of driving the 1-2, and 2-3 shift become deleyed and harsh, but the car acts fine when started and for the first couple of miles.
3. The shifting acting up is not constant, but I have a constant SES light on the P1870.
I have the stock A4 trannsmission in my 99 Z28, with an aftermarket Fuddle 3400 Converter I bought in December.
I did some research on this site and it seems my problem is either a tuning issue, or a bad Tourque Converter, which does not seem right as my TC is pretty new.
Any advice on how I should troubleshoot the problem?
I'm kind of worried about just turning the code off. I don't want to lose my transmission any time soon. If this is a genuine problem, I would like to remedy it before it becomes a bigger problem. But if it really just should be tuned out, because its not a real problem, then awsome. Ive had the converter since December and it never did this, so I'm kind of thinking this is a real problem. But thanks for the advice.
I looked this up the other day on another thread but this is what the code will do.....
OK, pulled up the specs on the code and it reads as follows;
p1870- trans component slipping
DTC stored in PCM
PCM inhibits TCC engagement
PCM commands max line pressure
PCM inhibits 4th gear if in hot mode
PCM freezes shift adapts from being updated
I'm almost certain this was the "death code" when I worked for GM a few years ago(before I got smart and got out!! lol) It may have been a fluke that caused it but I seem to remember more junk tranny's with that code than almost any other....except the good old broken sunshells.....
with the new converter etc, you may have to rewrite the ecm but not sure. Seems odd that it comes up now unless it was starting to have problems before you threw a converter at it too and now it wants to poop the bed.
OK, pulled up the specs on the code and it reads as follows;
p1870- trans component slipping
DTC stored in PCM
PCM inhibits TCC engagement
PCM commands max line pressure
PCM inhibits 4th gear if in hot mode
PCM freezes shift adapts from being updated
I'm almost certain this was the "death code" when I worked for GM a few years ago(before I got smart and got out!! lol) It may have been a fluke that caused it but I seem to remember more junk tranny's with that code than almost any other....except the good old broken sunshells.....
with the new converter etc, you may have to rewrite the ecm but not sure. Seems odd that it comes up now unless it was starting to have problems before you threw a converter at it too and now it wants to poop the bed.
Well I hopemy trannies not dying. It seems Fuddle recently went out of business, so I cant even have the converter fixed under warrenty if that is the problem.
PCM commands max line pressure I guess this would explain the harsh shifts, but I dont knwo why My 3-4 shift is fine.
The worst part is I was just abut to finally get my car inspected, overdue since January, and now I have another problem.
PCM commands max line pressure I guess this would explain the harsh shifts, but I dont knwo why My 3-4 shift is fine.
The worst part is I was just abut to finally get my car inspected, overdue since January, and now I have another problem.
the 3-4 shift may be where your problem lies if it still feels fine. With full line pressure applied it should bang hard even in the high gears. From what I understand the 3-4 clutches are a problem with a 4l60 anyway so it may be worth a look at. You could probably turn the light off long enough to get the inspection done if it's that huge of a deal. Turn it off right before you go to have it done and it may not reset before they do the inspection. Just an idea.......
I have never realy shifted into overdrive at WOT, or any high rpm for that matter. It's wierd from what your saying because the 3-4 shift is the only shift that still feels "right".
What would explain that it doesn't act up until Ive put a couple of miels on the car since start-up?
What would explain that it doesn't act up until Ive put a couple of miels on the car since start-up?
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without actually being able to put a tech2 on it and read the trans adapts it would be hard for me to judge it much further. You could look at the adapts and maybe be able to figure out why it went with an 1870 code. As for the reason it started acting stupid who knows? We built more trannies at Chevrolet than just about any other thing period. Most of the time is was the damned sunshells but the 4l60 will expire while you're sitting down for lunch sometimes it seems. Honestly if you want to take a chance just reset it and hope for the best. If something is truly wrong it will rear it's ugly head soon enough. Since the 3-4 shift still feels normal even with full line pressure applied I'd have to say the apply isn't working too well on that shift which generally means a clutch pack is going south and the rest will follow shortly. I hope for you it's just a fart in the system but usually a p1870 is the onset of a slow, painful death(to your wallet)
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the 3-4 shift wouldn't be an indication of the 3-4 clutches because the 3-4 clutches comes on in third and stays on in fourth the only difference between the two gears being that the band comes on.
for the record the difference between first and second is that the band comes on.
the difference in second and third is that the band comes off and the 3-4 clutches apply. the difference between third and fourth is the band comes on. thats every forward up shift in a nutshell.
for the record the difference between first and second is that the band comes on.
the difference in second and third is that the band comes off and the 3-4 clutches apply. the difference between third and fourth is the band comes on. thats every forward up shift in a nutshell.
Cody, I see what you're saying but it still wouldn't explain the "normal" feel to the 3-4 shift with full line pressure applied. Seems to me it would still apply(engage) very hard if there wasn't another problem within. Tell me where I'm thinking wrong please so I'll know better too!! 
What would explain that it doesn't act up until Ive put a couple of miles on the car since start-up? WHen I just drive it around town it feels fine...
Also I've noticed the change in feel and rpm (I think) when the converter locks-up is not as drastic as it used to be. But it might be that I have just gottne more used to the feel lockup and don't really notice it anymore.
Also I've noticed the change in feel and rpm (I think) when the converter locks-up is not as drastic as it used to be. But it might be that I have just gottne more used to the feel lockup and don't really notice it anymore.
when you have a p1870 you will have alot of strange shifting problems. the common fix is a new valve body due to wear in the tcc pwm valve which often explains the "only does it sometimes" complaint which is very common. this wear may be the number 1 cause but I've seen cases where a valve body didn't fix it. sometimes installing a trans-go shift kit will fix it. personally I think that there may be a couple different causes for this code such as aluminum porosity causing some pressure losses. but for the most part the valve body seems to be a cheap fix that is effective most times. if it was mine I would try a trans-go kit first and see if that will do it, being its the cheapest way to go and will more than likely fix the problem.
Thanks Cody, I decided against the shift kit and opted jsut to get the tranny tuned, but it looks like I be doing this now. I have no idea what a valve body is, yet I have read that it is the problem in a number of other posts on the P1870 code. Will the transgo fix the valve body?
I think the probelm may be due to my converter slipping in OD, as it only opccurs after a long period of driving in OD, like on the highway. Will this fix the problem, if thats the case or do I just need a new converter?
a new valve body should correct the slippage as the slippage generally comes from lack of holding power due to the pressures not being correct due to a sticky valve. provided it has slipped for too long and burned all the clutch material away so that the converter can't lock up.
Sorry for resurrecting an old thread, but I recently got P1870 on a long drive from school. I got it checked at autozone and it gave me a few explanations, but from research here. If I needed a new valve body or TransGo Shift Kit, where would I get them from?
Thanks (I have a v6 3800)
Thanks (I have a v6 3800)
P1870 happens when the converter is commanded to lock and the PCM detects excessive slip based on engine rpm verse vehicle speed. The transgo HD2 kit addresses this or as you mentioned a new valve body but on top of that many time I have found once this code throws you are also now in need of a converter.
How many miles are on your trans and whats the fluid look/smell like ?
How many miles are on your trans and whats the fluid look/smell like ?
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Alright I just checked the fluid and it seems im a bit low so I will be putting some in tomorrow and posting back to see if it remedies the problem.
About 4 years ago there was a newer motor put into it but other than that the clock is about 93-4k
About 4 years ago there was a newer motor put into it but other than that the clock is about 93-4k
Anybody? Id like to get this fixed before driving it more and causing more damage.
I did some searches to look at the converter to see if its bad but, I dont really know where that is.. :\
I did some searches to look at the converter to see if its bad but, I dont really know where that is.. :\