Difference between Engine Light and Vehicle Light

I would compare the Check Vehicle Light to the newer wrench light's Meaning that the car need's service and it is more then just a oil change etc it's something failing. From what you describe as the problem it sound's like there is a pressure problem in the transmission it's having trouble regulating the pressure so the transmission goes to max line pressure so it will shift hard in all the gear's. Then when you turn off the key it reset's the computer until the problem happens again and the hard shifting start's all over again.I have seen that same problem happen on the LS model saturn and the only code it will set is a code P1811 max trans adapative's what was happening there was the line pressure actuator in the valve body was failing. Also it was setting off the wrench light. You should be able to get the code's the normal way. Another thing I have seen cause hard shifting then turn the key off and on and it was ok again was a bad connector to the IAT sensor put's the transmission into max line pressure default mode to help protect the transmission from slipping and clutch damage.

When have U codes service vehicle light comes on
when have P codes service engine light comes on
when have C codes ABS light comes on
need a scan tool to check for U codes as an OBDII will not get U code s
check BCM for codes
good luck

Thanks Gang preciate the Info.

.