P0750 code
 

P0750 code..

We parked our 96 volvo 850 about a year ago and other than the coolant reservoir over pressurized and the consequential over heating (I'm assuming thermostat) it ran smooth and shifted no problem.

I finally put a jump to it today and and as soon as I got it into my driveway, it went into limp mode (flashing upwards arrow on dash) and won't move forward. I reset the codes and it came back on when I put it in gear. The battery is ridiculously weak (could that be a contributor) and after I let it charge for about 30 minutes, and turned the car over, the light was gone. Until I put it in drive again. Fluid level looks OK.

Any thoughts or suggestions?

Thanks!

Trouble code P0750 means Shift solenoid A malfunction

yes, low system voltage can cause odd CELs. its a fairly standard practice to clear them and see if they return. Also with cars that have been sitting you can get corrosion on contacts that can give an odd error or two.