Chrysler Repair: 1999 300M will not go out of 1st gear, vehicle speed sensor, shift cable

Question
--Ron, We did exactly what you said to fix the problem and it worked.Now how do we get rid of the check engine light? Do you happen to know anything about Grand Prixs also? Thanks,Larry
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Followup To
Question -
Ron,Here we go again just took the car for a drive and it will not go out of 1st gear and the speedometer is not working and the miles are not adding on the car.We have had not had any problems till we took it in for the A/C problems we contacted you about.Could they have knocked something loose in fixing the A/C? Thanks,Larry
Answer -
Hi Larry,
There is a vehicle speed sensor located on the transmission which is responsible for both the signal to run the speedo/odo and the function of the transmission (e.g. proper shifting). The sensor is either defective or the electrical plug for it was dislodged by the AC mechanics. If you look at the side of the trans you will find it near to where the shift cable is attached (on your car that would be on the left (driver's) side of the powertrain unit, have a helper shift the gear lever to make a motion/noise to help you locate it). You will see where that shift cable is attached to the transmission. Just to the rear of that shift "tower" to which the cable is attached is the vehicle speed sensor (this is about mid-line as regards the vertical height of the trans). There is another sensor at that same height on the forward side of the shift tower, which is the sensor that measures the speed of the torque converter output turbine. The trans needs both of the sensor signals to run properly.  But the one you want to inspect is the rear one. Check that's its plug is not loose or damaged. You might try and spray its teminals with a little solvent. Also inspect the wire harness for any signs of damage as far as it can be traced.  Then reconnect and see if the problem is solved. If not, then you can either verify the wires are patent thru to the places where they go using an ohmmeter, or buy a new sensor (and assume the wires are not the problem). The sensor just screws out and back into the trans housing, so you could do it yourself.
But that sensor is now out of action and that is exactly what would cause your symptoms.
Roland  

Answer
Hi Larry,
I'm pleased that it was fixed so quickly. The check engine light will go off in 75 or so key off-on-off cycles, if the fault that caused the light in the first place is now corrected. So wait a bit of key cycles of normal driving usage and see if it doesn't go off by itself.
I have to admit total ignorance of GM cars, other than the generic items so I probably won't be of much help.
Roland