p1870 code
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Teching In
Joined: Jan 2003
Posts: 2
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From: spring,texas
p1870 code i recently purchased an 01 t/a with several mods including and yank 3500 convertor,the problem i am having is about once every two or three days it will turn on the service engine soon light and will start to shift very hard.i found the code was a p1870 code(trans component slipping) and the trans is not slipping at all,so my question is,will this happen due to the convertor slip or is there a way to change the window for slippage in the pcm to avoid this problem. thanks in advance for any info.
The code is most-likely being caused by torque converter slippage. That can be a secondary symptom though.
You have three choices, the first two with two options each.
1. You can install the Sonnax TCC regulator valve along with reaming the bore in the valve body for it, OR, install a TransGo shift kit which includes a better-designed TCC regulator valve that will not allow so much fluid to slip past.
2. You can do the Pulse Width Modulation (PWM) delete modification to the valve body, OR, reprogram the PCM to eliminate PWM all together.
3. Replace the torque converter with one that has a fresh clutch made of carbon fibre.
Could be other stuff too, but P1870 is usually TCC.
You have three choices, the first two with two options each.
1. You can install the Sonnax TCC regulator valve along with reaming the bore in the valve body for it, OR, install a TransGo shift kit which includes a better-designed TCC regulator valve that will not allow so much fluid to slip past.
2. You can do the Pulse Width Modulation (PWM) delete modification to the valve body, OR, reprogram the PCM to eliminate PWM all together.
3. Replace the torque converter with one that has a fresh clutch made of carbon fibre.
Could be other stuff too, but P1870 is usually TCC.
It could be a lot simpler than that. That code often pops up if torque management has not been deleted and the code turned off. If you bought the car from a dealer i'm willing to bet they reflashed the pcm so it lost its tune. The private seller could of also returend the car to stock. I'd contact the previous owner and ask if it was tuned, and if so where to get it reflashed or tuned.
Thats not giving him any sense of hope 
Teching In
Joined: Aug 2004
Posts: 23
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From: Tampa, Fl
Do you know if the trans was rebuilt? When I bought my car the guy I bought it from had a stage 3 shift kit and a whole bunch of other crap (including the PWM delete which f'ed everthing up). Find a reputable trans shop and have it rebuilt with carbon fiber everything and you should have no problems. It cost me about 1800 but I also bought a new tci 3200 and a deep pan.
