Z06 , 73,000 mi. Check Engin Light

[Allen Mancini]

Hi,my check engin light comes on and I went to auto zone and checkit on acode reader and it said that code P0803 .Up shift solenoid circuit malfunction
so I reset it light went out for a day.I went back when it came on again and reset it again .Next day on again.So then I went to the error code display and came up with a code 28-TCS C1214 H it says that it is Solenoid Valve Relay Contact or Cail Circuit Open.I reset it and again light gos out It said no codes Pass.Drive it a day light come on again . I check the error code and its the same mesage . Where is the solenoid Valve Relay contact and also the coil circuit open. How do I go about fixing this prob????
I got the car it already had on it the shift bypass !st to 4th.I would like to try taken it out and see if things get better. Can someone tell me where the bypass is??? THANK YOU FOR ANY HELP Allen

[sreve]

thats an abs code, the relay is built in to the ebcm electronic brake control module. sounds like a history code anyway it won't turn on the check eng light. no abs light no worries.
bypass proably the cause of the light as you suspected.