Shift Range Inhibited - Still

[Robbfuzz]

Hello folks

I have replaced the ignition switch and the nsbu switch and am still getting "Shift Range Inhibited." It is throwing the following codes
841
846
848
700
700 pd (whatever that is)

As far as I know, the truck is stock. There is no programmer currently (might have been before I bought it, screw holes in lower dash near plug) and everything under the hood that I can see looks stock.

Any suggestions would be greatly appreciated!!

Thanks
Tracy

[clinebarger]

P0700.
This code indicates that a related transmission code was set in the transmission control module (TCM). The ECM receives the TCM DTC information over the serial data circuit. The ECM turns "on" the MIL.

P0841.
Pressure Control (PC) 'C' shift valve commanded to the "on" (stroked position), and the TCM detected that the pressure switch 'C' status remained "off" for 1-5 seconds (actual time depends on transmission fluid temperature). The pressure switch manifold (PSM) is a multiple-switch assembly with 3 normally open (N.O.), and one normally closed (N.C.) pressure switches. The PSM 'C' pressure switch monitors the position of the PC 'C' shift valve position and relays it to the TCM. When the PSM 'C' pressure switch is in the open state, the C shift valve should be in the un-stroked position.

P0846.
Pressure Control (PC) 'D' shift valve commanded to the "on" (stroked position), and the TCM detected that the pressure switch 'D' status remained "off" for 1-5 seconds (actual time depends on transmission fluid temperature). The pressure switch manifold (PSM) is a multiple-switch assembly with 3 normally open (N.O.), and one normally closed (N.C.) pressure switches. The PSM 'D' pressure switch monitors the position of the PC 'D' shift valve position and relays it to the TCM. When the PSM 'D' pressure switch is in the open state, the solenoid 'D' shift valve should be in the un-stroked position.

P0848.
Shift Solenoid 2 commanded to the "on", stroked position, and the TCM detected, during steady state operation, that the PSM 2 switch status remained "off" for 0.125 seconds (actual time depends on transmission fluid temperature). The pressure switch manifold (PSM) is a multiple-switch assembly made up of 3 normally open (N.O.) pressure switches and 1 normally closed (N.C.) pressure switch. Pressure switch 2 (PS2) monitors shift valve 2 positioning and relays it to the TCM.

Check the transmission fluid FIRST!!!!!!

Sounds like either a wiring/connection problem or the PSM/TFP switch assembly is bad if the fluid level is OK.

The component im talking about can be called 2 things.....
PSM, Pressure Switch Manifold
TFP, Transmission Fluid Pressure switch
Its located in the transmission pan bolted to the valve body.

[Robbfuzz]

Thank you so much clinebarger. I have checked the fluid level, that was one of my first thoughts. I will recheck it again just to be sure and I will check out that switch assembly.

Thanks again
Tracy

[catman3126]

not too long ago there was a guy on here with the same problem and he ended up finding out it was the filter under the pan sucking air because the seal where filter screen connects to the valve body as damaged. did you just buy this rig or did it have a trans service recently?

[catman3126]

Ohh i see you did just recently get it. sounds like you have checked pretty much everything.....might be time to drop the pan and check the filter...just a thought.

[shawjohn2nd]

Hey my truck was also giving me the shift range inhibited message, and I also replaced the Nsbu switch, I had it back to the dealer again. They called and stated that they found transmission fluid in the wiring harrness inside the tranny, I guess there is a gromet in there that wears out, they changed that harness, and the truck went back to normal. They said they have only seen this in two or three other trucks, lucky for me mine made number four. I hope this helps

[PrivatePilot]

Thread moved to Allison forum from engine forum.

[dubbzie]

HI,
Anyone happen to have the allison part numbers for the pressure switch manifold and the internal wiring harness? 2009 lmm.
Thanks.

[Ramblinrodney]

Pressure switch manifold 29542585 and internal wiring harness 29545307 Hope some one else can verify those are the right numbers. This is where I go to look up parts http://parts.nalleygmc.com/

[dubbzie]

Went to order parts today. I was informed that the pressure switch manifold part number has changed to the newer part number, and is now 29546972. Supposed to be the improved version. And the internal harness number 29545307 is not an allison number.
Thanks.