Limp mode, PRNDL fuse hot, no power to 4L60E

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Z71_Zimmerly

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Hey guys,
I'm stumped on this one.
1998 K1500, 4L60E in limp mode. High idle, won't shift from 3rd. It was intermittently doing this a few times in the last couple weeks, but seems to be stuck in limp mode now.
P0740 - TCC enable solenoid circuit electrical
P0785 - 3/2 shift solenoid circuit electrical
P1860 - TCC pulse width modulated solenoid control circuit
I had a new ignition switch, so decided to replace it, in hopes it would solve the issue. It didn't.
I haven't noticed any issues with my guages going out, as a lot of others have.
I have power at my PRNDL fuse, but when I unplug the harness from the passenger side of the trans, I'm not finding any power on any pins in that end of the harness.
This is where I'm stuck. I've looked at pinouts of various plugs, but can't find the ones I need, and just feel lost when it comes to this. I can do most auto electrical stuff, but this thing is overwhelming, because have no idea if I'm going about this the right way, as I haven't found anyone else who has experienced this.
After reading-up a bit on things, I wondered if I could bypass the trans harness and send my own wire from the PRNDL fuse to the pink wire on the trans side of the harness.
Any help is appreciated. Thanks!
-Jacob

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1997

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Google, 4L60E_80E_CODE_BOOK, should help you out.
 

LovesDunes

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Hey guys,
I'm stumped on this one.
1998 K1500, 4L60E in limp mode. High idle, won't shift from 3rd. It was intermittently doing this a few times in the last couple weeks, but seems to be stuck in limp mode now.
P0740 - TCC enable solenoid circuit electrical
P0785 - 3/2 shift solenoid circuit electrical
P1860 - TCC pulse width modulated solenoid control circuit
I had a new ignition switch, so decided to replace it, in hopes it would solve the issue. It didn't.
I haven't noticed any issues with my guages going out, as a lot of others have.
I have power at my PRNDL fuse, but when I unplug the harness from the passenger side of the trans, I'm not finding any power on any pins in that end of the harness.
This is where I'm stuck. I've looked at pinouts of various plugs, but can't find the ones I need, and just feel lost when it comes to this. I can do most auto electrical stuff, but this thing is overwhelming, because have no idea if I'm going about this the right way, as I haven't found anyone else who has experienced this.
After reading-up a bit on things, I wondered if I could bypass the trans harness and send my own wire from the PRNDL fuse to the pink wire on the trans side of the harness.
Any help is appreciated. Thanks!
-Jacob

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Did you ever figure out what the fix is?
 

NickTransmissions

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Did you ever figure out what the fix is?
Are you having a similar issue with yours? For those above set of codes in the OP the problem is usually the transmission wiring harness as its not likely all three solenoids failed (to be fair, the TCC enable solenoid is integrated into the harness).
 
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