Trannyman doesn't need to be here to answer this one. There really is not temporary fix for your situations. Shift solenoid is failing and probably more inside the trans. If you want to diagnose further you can but it's a waste of time. I know that you say that your code was with the 2-3 but with the chart listed below I would say that your issue is more with the 1-2 solenoid.
Taken straight from Triple Edge Performance - Home Page ....you can use the chart to determine function with using a multimeter.
Connect Pins Solenoid Resistance at 68*F 190*F
A-E 1-2 Shift Solenoid 19-24 24-31
B-E 2-3 Shift Solenoid 19-24 24-31 T-E TCC/PWM Solenoid 10-12 13-15 C-D EPC Solenoid 3-5 5-6 S-V Input Speed Sensor 893-1127 1132-1428 M-L TFT Sensor 3164-3867 225-285
Output Speed Sensor 981-1864
Shift Solenoid Patterns for each gear
Range 1-2 Solenoid 2-3 Solenoid
Park ON ON
Reverse ON ONNeutral ON ON
1st Gear ON ON
2nd Gear OFF ON
3rd Gear OFF OFF
4th Gear ON OFF
