Has any one had a problem with the engine electrical sign keep showing?

i have a Astra Ls 2003 model and have taken to a garge to be checked and pluged into the machine to check all systems and it came back with no problems but a in put voltage of 32volts but i still keep getting the spanner and car symbol showing on the dash board after driving the car 200 yds up the road after first startingthe car in the morning if i pull in swicth the engine off and restart it the light goes out does any one else have the same problem and if so how was it solved

pete luther
August 2009