converter lock-up issue
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Teching In
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converter lock-up issue I am tuning with hp tuners and I have asked tis same question. My converter is disengaging lock-up when there is no load, and will re-engage when I start to accelerate. The transmission is fine. it is something in the tune that I can't quite figure out. Does anyone have a suggestion? TIA
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From: Alaska
In for answers here.
Having rather violent TCC LOCK/Unlock problems as well. Took all the ""misfire Tables" to max value.
Workaround at present is to disable Lock-up in Tow-Haul mode, and anything over 70 MPH I have to run UN-Locked in Tow/Haul.
Can manually LOCK converter in Diagnostics, and it WILL stay locked.
Something mysterious in my P59 2 Bar SD tune is THRASHING my TCC solenoid at highway speed.
Having rather violent TCC LOCK/Unlock problems as well. Took all the ""misfire Tables" to max value.
Workaround at present is to disable Lock-up in Tow-Haul mode, and anything over 70 MPH I have to run UN-Locked in Tow/Haul.
Can manually LOCK converter in Diagnostics, and it WILL stay locked.
Something mysterious in my P59 2 Bar SD tune is THRASHING my TCC solenoid at highway speed.
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Teching In
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Y issue starts at 45 mph and up. My converter will lock and stays locked until I hit a flat area or I let off of the gas. If I am coasting down a hill and the truck continues to increase in speed it stays locked. If I am going up a hill it stays locked, but If there is any discrepancy between the TPS and the speed of the vehicle it will disengage and acts like it is floating between 3rd and 4th gear until I accelerate. Then it re-engages and starts pulling again.
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From: Alaska
There seems to be a LARGE number of condition(s) and aparameters that can or WILL cause the PCM to Un-lock the 4L80 TCC.
I will begin a list, and hopeful that some experts will ADD to the list, or make corrections to my attempt.
P59 TCC Unlock Parameters:
1) Brake pedal switch 12 volts= "Can Lock".... 0 Volts WILL UN-Lock
2) Trans Temp sensor Open Circuit default to -40 Degree temperature WILL UN-Lock
3) ISS speed not equal to Crankshaft speed ( apparent converter slip) WILL UN-Lock
4) TPS 0% ( coasting) WILL UN-Lock
5) 1st gear cannot Lock
6) 2nd thru 4th Gear CAN Lock above TCC speed vs gear table, but subject to Min-Max TPS settings.
7) Misfire detected TCC WILL UN-Lock
I will begin a list, and hopeful that some experts will ADD to the list, or make corrections to my attempt.
P59 TCC Unlock Parameters:
1) Brake pedal switch 12 volts= "Can Lock".... 0 Volts WILL UN-Lock
2) Trans Temp sensor Open Circuit default to -40 Degree temperature WILL UN-Lock
3) ISS speed not equal to Crankshaft speed ( apparent converter slip) WILL UN-Lock
4) TPS 0% ( coasting) WILL UN-Lock
5) 1st gear cannot Lock
6) 2nd thru 4th Gear CAN Lock above TCC speed vs gear table, but subject to Min-Max TPS settings.
7) Misfire detected TCC WILL UN-Lock
TECH Fanatic
Joined: Jul 2022
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From: Alaska
edit:
Checking back into thread: OP Hope you have made progress with your issue/
Update from My End:
Pretty sure I have my 4L80 swap TCC Lock-up/unlock issue FIXED: I had failed to include " Trans Diagnostics " check box when I did 4L80 segment swap to P59.
Added the Trans Diagnostics and TCC (so far )seems to lock up as commanded with the BlueCat tables.... and STAYS Locked.
Last edited by Full Power; Jul 25, 2024 at 01:14 AM. Reason: spell chex
Thread Starter
Teching In
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I found my problem and it wasn't the tune. My converter was bad, and with replacing the converter it straightened out my tune. From my converter malfunctioning it was giving my pcm a fit when I was tuning the VE and MAF. I also think it was causing a false knock issue. Now it is down to fine tuning and maybe adding some timing to see how much the truck picks up.
