Chrysler Repair: P1776 on a 300M 2002, powertrain control module, solenoid switch

Question
Hi Roland,
About a month ago, I put my car in reverse to get out of my driveway and when I put it back to drive the car would not move. This happened twice. Last week I am driving down the highway and had to slow down. My car "kicked" and then it got stuck (my guess in 2nd gear) and it would not shift up. In both cases the problem went away after I restarted the car. I took the car to a shop and the diagnostic code came back as P1776. Can you tell me what the problem is and what is usually done to resolve this?

PS. Do you have anything from the Chrysler 300M manual that would show a step-by-step diagnosis and repair?

Answer
Hi Gerry,
That codes means that the Low-Reverse solenoid switch valve (one of four such valves) is latched in the low-reverse position.
The possibilities are:
the solenoid switch is falsely latched
the low/reverse pressure sensing switch itself is bad
the transmission control relay output circuit is open
the control circuit (sense) of the l/r switch is open, shorted to ground or shorted to voltage.
The control relay's output is on pin #4 of the 8-pin plug of the transmission (red wire); you could verify that the wire has 12V on it when you are idling (and I guess I would put it in gear with the brakes applied). Also examine/shake the wire for intermittent connection possibility.
The solenoid sense circuit (a pressure switch) connects pin # 2(dark green) to pin 29 of the powertrain control module. You could verify that  connection and monitor it for voltage to fluctuate between 0V and some measureable V when the trans is shifting normally, and to loose that fluctuation when it is not, which would verify the circuit is OK.
If that proved to be OK, then I would suspect the pressure switch isn't responding and needs to be changed.
The solenoid box (which contains the pressure switches and solenoids) is removeable after you drop the pan and remove the valve body, and so it would not seem to be an horrendous expense (when compared to a rebuild). I haven't done this myself so I can't comment on doing-it-yourself as an amateur with no trans experience. It appears that most such repairs are accomplished by replacing the entire solenoid pack as that is what other owners tell me is done when problems like this occur.
I would try to find a competent independent shop that know the Chrysler trans and discuss it with them as to the cost of replacing the solenoid pack and the cost of the pack. I probably can copy from an '04 manual some pages that show how to change the solenoid pack and send those to you by email, but I would need your email address to do that. The web site asks you for that, but the 'expert' doesn't have access to that information.
Roland