Hey to all, well I'm at a bit of a stump, so let me begin. got my 2001 Blazer LS 4x4 W/ Auto (NP8) scanned and got these codes: P0740, p0758, p0785, p1810, p1860, p0753. So after some reading on here I checked all my fuses, yup. Checked for power in fuse #11, Yup. Checked for power from the pink wire that goes to my transmission, Pin "E" I do believe, and I have power on ON / RUN from my ignition. Also note, my 4x4 isn't working as well, 4 button selector switch has it's illumination lights, but no selection lights. replaced the TCCM with no luck, and I am able to get 4x4 by bypassing the vacuum switch on the firewall with a hose joint. (tried a couple vacuum switches as well to make sure that wasn't the problem) Can anyone help me with this nightmare?

 

P0740 - Torque Converter Clutch Circuit
P0758 - Shift Solenoid B Electrical
P0785 - Shift Timing Solenoid
P1810 - TFP Valve Position Switch Circuit
P1860 - TCC PWM Solenoid Circuit
P0753 - Shift Solenoid A Electrical

These Should help you out.. Sounds like you took the whole harness out somewhere.

 

I'm getting power to the pink wire going into the Neutral Safety Switch. Could this switch be the problem? if not, yeah might have to just replace this section of harness.

 

well I'm down to 4 codes, P0740 P0753 P0785 P1860. Motor is running like a champ after I replaced the spider injector, but unfortunately still in limp mode and still no 4x4. tried 3 TCCM's and 2 4x4 switches. All fuses are good. Connections along the harness all look good as well. Changed 2 out of 3 O2 sensors, will change the last one and see if there is any difference. Any ideas, suggestions appreciated.

 

Check the harness connector on the transmission: Right front corner, plugs in vertically just above the pan. This harness feeds all of the solenoids in the transmission. Due to its location, it's exposed to road slop, mud, sand, water, salt, etc etc, all of the things that promote corrosion. Clean it out, dry it out, and put silicone dielectric grease in the connector. Just a thought

 

will try that today, thanks, will let you know the results!

 

It was unplugged, cleaned and plugged it back in, but no difference

 

With the engine at idle, check both terminals, (on top of the fuse, do not remove the fuses) of all fuses with a volt meter or test light, in both the underhood and instrument fuse panels. Post your results.

EDIT: Pay close attention to these:
Instrument fuse panel:
#19 RDO
#11 Cluster
#22 ABS
#15 4WD
#8 CTSY LP

In the underhood fuse panel:
ECMB
ECM1
ATC
BTSI
CRANK

 

Update: ATC fuse must have burnt when I plugged in the harness to the tranny, replaced fuse, and 4x4 is working properly and excellent! still in limp mode tho, CRANK fuse shows no power @ idle, rest are all good.

 

what code remains ?