Put 4l80e tcc on a switch, and lost OD?

[letitsnow]

I have done more research on this and have found others that have had trouble getting the obdII 4l80e tcc to lock up by adding the ground switch to the brown wire.

I have read that you can make it work if you wire a 50 ohm resistor inline with a ground to wire #27 (trans fluid temp) on the red connector, but if you do that the trans will shift at full line pressure - and then you should shift manually to unload the clutches.

Another interesting note - I made this work on my obdII '98 s10 with the 4l60e, but that trans has 2 tcc solenoids listed - a tcc solenoid, and a tcc pwm solenoid. The 4l80e only has one tcc solenoid.

 

[tayto]

the 4L80E TCC solenoid is PWM controlled, it is not an on/off arrangement like a 4L60E solenoid.

 

[letitsnow]

the 4L80E TCC solenoid is PWM controlled, it is not an on/off arrangement like a 4L60E solenoid.

The 4l60e is pwm also, after a certain year. My '98 says pwm.

 

[tayto]

Nope, the TCC solenoid is an on/off arrangement and has been the same basic solenoid since '82 until the end of the 4L60E production. This is why you are able to control lockup with a switch easily. You should go read some more on what valve is PWM controlled and how it affects lockup.

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[tayto]

i'll add a bit more here... without internal mods even with your "switched" TCC, it is still only partially applying at times, unless certain conditions are met in the PCM. Not only are you making more work for yourself but your still using GM's crappy PWM controlled TCC. hardly an "upgrade".

 

[letitsnow]

Thank you. That was actually useful information. I am a bit surprised.

 

[letitsnow]

More info to add - I tried T'ing into the brown (instead of cutting) tcc wire and it worked for about 15 minutes, then went into some kind of limp (?) mode and would no longer shift into OD. I had to disconnect the battery cables for a while, then it started shifting normally again. This poor transmission...

The only thing that I haven't yet tried is the 50 ohm resistor/tft trick. I doubt that would work either, as I believe you are fooling the pcm into thinking that the trans is too hot, which would then put it into limp mode again.

Without the ability to tune the pcm yourself, I think that this truck is just too smart to trick.

 

[tayto]

you need to generate a pwm signal. full stop.

 

[letitsnow]

I tried the 50 ohm resistor t'd into the trans temp wire, it didn't make much difference. GM's pcm wins this battle.

If I could do this all over, I'd buy an obdI truck. I hate that f'en pcm.