Code p1870
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From: Fort Leavenworth KS
Code p1870
I'm awaiting a call from my Tuner and I do want to thank those that tried to help out already. Here it is; when I got the gears changed from 2:73 to 3:42 and sy3500. The car ran great back home, since then I have driven around town and then yesterday a slight hesitation while driving and then the engine light came on. I pull off into a parking lot and then headed home. Now, like a couple of others from the forum from 1st to 2nd shifts really hard. I'm guessing it's the LS1 edit. While I wait for that phone call 1. Is the car safe to drive? 2. If I get Edit again will I have this same problem? 3. Should I go a different programing route? and finally or am I really confused? I do live in Kentucky and I have emailed a few members looking for LS1 Edit but no luck. Any help would greatly be appreciated. Oh yea the code is 10 PCM P1870 .
Le Mans Master
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From: Greenville SC
Re: Code p1870 (NoProblem)
DTC P1870 Transmission Component Slipping...
"The PCM monitors the difference between the engine speed and the transmission output speed. In D3 drive range with the TCC (torque converter clutch) 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 +40 rpm.
When the PCM detects excessive TCC slip when the TCC should be engaged, then DTC P1870 sets."
Do a search on 3.42 gear swaps or some variation of that phrase, this has been discussed here before I think. Hope I was of some help.
[Modified by Tom Steele, 7:27 PM 9/5/2002]
"The PCM monitors the difference between the engine speed and the transmission output speed. In D3 drive range with the TCC (torque converter clutch) 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 +40 rpm.
When the PCM detects excessive TCC slip when the TCC should be engaged, then DTC P1870 sets."
Do a search on 3.42 gear swaps or some variation of that phrase, this has been discussed here before I think. Hope I was of some help.
[Modified by Tom Steele, 7:27 PM 9/5/2002]
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From: Fort Leavenworth KS
Re: Code p1870 (NoProblem)
Thanks Tom.
Anyone, If I can't drive it back to the Tuner and LS1 Edit is not available around here can I still get another program like Ed Wright? Why can't I live in California, Texas or someplace with tuners nearby.
Anyone, If I can't drive it back to the Tuner and LS1 Edit is not available around here can I still get another program like Ed Wright? Why can't I live in California, Texas or someplace with tuners nearby.
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From: Murphy TX
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Re: Code p1870 (NoProblem)
Programming is your problem. A search for P1870 will turn up loads of threads. There are a few related to LS1-Edit and this issue in the Scan & Tune forum.
When P1870 sets the PCM commands max line pressure and prohibits the TCC from engaging. I disagree that this will damage your converter, the PCM is in fact making it's life easier. You can clear the code as you would any other (even while driving if you're coordinated :) ) although it will surely return since you can't correct the condition. If you want to convince yourself that this is the issue, you can hook up a scan tool and observe the TCC Slip Speed parameter. You'll see values like ~500 RPM when they should more typically be ~30-40 RPM. It's not slipping that much, the value is miscomputed by the PCM software.
LS1-Edit doesn't do anything tricky to your PCM that would prohibit another programmer from manipulating it if you have to go that route. I would expect my tuner to fix this. How far away is your tuner?
[Modified by ToplessTexan, 8:22 PM 9/5/2002]
When P1870 sets the PCM commands max line pressure and prohibits the TCC from engaging. I disagree that this will damage your converter, the PCM is in fact making it's life easier. You can clear the code as you would any other (even while driving if you're coordinated :) ) although it will surely return since you can't correct the condition. If you want to convince yourself that this is the issue, you can hook up a scan tool and observe the TCC Slip Speed parameter. You'll see values like ~500 RPM when they should more typically be ~30-40 RPM. It's not slipping that much, the value is miscomputed by the PCM software.
LS1-Edit doesn't do anything tricky to your PCM that would prohibit another programmer from manipulating it if you have to go that route. I would expect my tuner to fix this. How far away is your tuner?
[Modified by ToplessTexan, 8:22 PM 9/5/2002]
Drifting
Joined: Sep 2001
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From: Memphis Tn
Re: Code p1870 (NoProblem)
I drove for 8 months without tuning. 3:73 gear and a 2600 TC. Always slipped at 57 mph on expressway. Never slipped at WOT in 3rd. But I wouldn't race it without the tuning. I do not see why you would not be able to drive it around. Nothing is going to happen unless your transmission slips alot and it gets hot. Drive around monitoring it's temp on the dash. You should be fine til tuning.
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From: Fort Leavenworth KS
Re: Code p1870 (NoProblem)
Thanks Topless,
I did a search but I guess a deeper one is in order. I'm sure that my Tuner (who is good) will give me solid advice when he returns my call. In the mean time I wanted to get educated on the issue from the "corvette gurus" before a 6 hour drive one-way had to happen.
ScreaminDemon: I haven't driven it since I parked it, but the only big difference I recall was that shift from 1st to 2nd. When the engine light first came on I did a quick scan and all the guage readings seemed to be fine. Thanks for your input.
I did a search but I guess a deeper one is in order. I'm sure that my Tuner (who is good) will give me solid advice when he returns my call. In the mean time I wanted to get educated on the issue from the "corvette gurus" before a 6 hour drive one-way had to happen.
ScreaminDemon: I haven't driven it since I parked it, but the only big difference I recall was that shift from 1st to 2nd. When the engine light first came on I did a quick scan and all the guage readings seemed to be fine. Thanks for your input.
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From: Murphy TX
Cruise-In II Veteran
Re: Code p1870 (NoProblem)
Versions of LS1-Edit did not handle this correctly prior to v1.1, in particular v1.05 (the first public release with explicit gear scaling for the C5) did not. If you were tuned with an older version you need to either a) reverse the gear scaling changes w/ the older version and try again with v1.1 or b) start again with the factory flash, scale the gears, and copy over the remainder of your tuning. It's easier to be sure of what you have with option b). Your tranny isn't actually slipping any more than it ever did but the code is immensely annoying. If you're really bored, I babbled a little about this issue here: http://temp.corvetteforum.net/c5/fro...arameters.html
Pro
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From: Orlando, Florida
Re: Code p1870 (ToplessTexan)
Mine did this after a gear swap & Hypertech programing....
I had to go to Powerloader program to correct the gear change & avoid that code & tranny tightening...
On mine I was able to re-set the codes & it would be OK for a while, until it re-set the code again.. Mine usually happened after interstate driving, but was OK around town.
I had to go to Powerloader program to correct the gear change & avoid that code & tranny tightening...
On mine I was able to re-set the codes & it would be OK for a while, until it re-set the code again.. Mine usually happened after interstate driving, but was OK around town.
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From: Fort Leavenworth KS
Re: Code p1870 (NoProblem)
Goldman,
Thanks for the information. My Tuner called and wants me to check a couple of things and we'll go from there. Should be no problem. Or I can go the route of a KY corvette repar shop that stated I have a bad bearing and now there are shavings in the fluid causing the code. Something about the TC is too tight? Anyways he went on to say he needs 3 days to fix and $1,800 (tranny rebuild). He had a couple of c4s but not any c5s. We happen to come accroos this place when the family and I went for a drive. I smiled and thank him for his time :)
Thanks for the information. My Tuner called and wants me to check a couple of things and we'll go from there. Should be no problem. Or I can go the route of a KY corvette repar shop that stated I have a bad bearing and now there are shavings in the fluid causing the code. Something about the TC is too tight? Anyways he went on to say he needs 3 days to fix and $1,800 (tranny rebuild). He had a couple of c4s but not any c5s. We happen to come accroos this place when the family and I went for a drive. I smiled and thank him for his time :)
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From: Fort Leavenworth KS
Re: Code p1870 (NoProblem)
Not yet. Tomorrow I'll go to the self help auto shop on post here (if the're open) and check the rear-end fluid and see if they have a scan tool. I noticed your post for "TNT" on the parameters. Again thanks for the info.
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From: Murphy TX
Cruise-In II Veteran
Re: Code p1870 (NoProblem)
Forgot to mention that you can avoid the code altogether while on surface streets if you leave the gear selector in '3'. Not much help on the highway but it can keep you from fooling with clearing codes while driving around town. ;)
