On this car the map is connected directly to to the intake, under it is the pcv valve, there are several seals involved, loss of vacuum would would cause a high voltage signal, it could be bad, the engine could have a vacuum leak, the seals could be missing from something being worked on prior. No quick answer here, this needs to be looked at by someone familiar with the causes of the condition, if it has serious misfire issues this can set the code. Check this link.
http://service.gm.com/gmspo/mode6/pd...c38K_H__yE.pdf