explain how u washed it. hose,pressure,bucket,ect
if the temp connector was full of water then it might short it causing light to come on.
might clean throttle linkage and stepper with wd40 or something better.
have washed mine with hose and pressure w/o prob. of coarse u can find other advice.mine screws up every now and then i just give it quick and let off revs about 5 times.
the temp light would set a code and might make it run bad. u should find out what code is in the ecu