I picked up a 2000 Jimmy 4wd cheap, but it has issues. It would not shift out of 4-low. Service 4wd light was on. I could hear the encoder (EM) actuating, and the TCCM relays clicking. I just replaced the EM - set the selector to neutral for installation (made good, solid detents) - now it will not shift out of neutral. I do not hear the encoder doing anything. Checked the wiring best I could while on my back - didn't see anything obvious. Service 4wd light sill on.

I can't pin the DTC & pull codes since I don't have a pin 13 - DTC wires only @ terminals 2,4,5 & 16. Disassembled TCCM & cleaned terminals. Front actuator seems to be working fine.

Switch lights up - the selector button flashes when pressed while the TCCM actuates - then nothing... the lights go out.

Tried resetting to no avail

Ideas?

Everything I've read says to ground terminal 13 to pull codes... I ain't got no 13

 

Pin 13 is for NV233 transfer cases. Your transfer case is a NV236, ground pin #16 and read the flashes on the switch.

 

Thanks Cap'n!!

I will give that a whirl today

 

Same issue...

With key on, switch lights cycle, then it displays "4-high" constantly flashing while TCCM relays click - followed by one last relay "click" & switch lights going out.

Grounded #16 to no avail.

I did manage to blow the 15A cig lighter fuse while attempting to pull codes
whoops...

 

I had the same issues with my 4wd and traced the problem to the encoder brake not releasing when the encoder tried to shift.I suppose the tccm was to blame,but it did the same thing with a replacement and a new encoder motor.I took the brake off of the encoder motor to see if it would work,and it did,so I left it with the brake off and it works fine.a little touchy when shifting out of 4 back to 2,sometimes it hits neutral in the case and I have to hit the 2 hi switch again.Got tired of throwing money at it,so I'm using it as is,but it does work now.

 

Please elaborate... in detail so that I'm less likely to snafu

 

The encoder motor has a plastic cover on it. I removed the plastic cover and on the end of the motor is an electric brake mechanism.It gets released when the tccm sends a signal to it when it calls for the encoder motor to shift.If the signal isn't sent,or the wiring is damaged,or the brake is faulty,the brake will not release and the motor cannot overcome the drag of the brake and will quit trying to shift the motor (the systems kicks out). I removed the brake assembly from the end of the motor and put the whole thing back on.I just taped off the 2 brake wire leads so they wouldn't cause any problems.The brake mechanism is bolted onto the end of the motor and can be taken off without disturbing the motor.

 

Tried that also... to no avail.

I installed encoder sans motor cover & tried selecting with & without the brake plugged in. I've even tried another encoder & tccm.

I manually shifted into 4hi, and internally reclocked the encoder & position sensor. It's in 4 hi, and will select 4auto, but that's pretty much it

 

Just unplugging the brake won't work,you have to take the brake off the motor because the brake is locked until it gets the signal from the tccm.So if the tccm isn't sending the signal,the brake is bad or the wiring to the brake is bad,or the brake is unplugged,no release.