[klinn]

When you connect the vacuum pump to the EGR (where the vacuum line connects), it should pump up and hold vacuum. If it doesn't the EGR diaphram has a leak, and the EGR valve will need to be replaced. As far as the knock sensor replaced without battery disconnected, don't worry about that. After you test/repair the EGR system, disconnect the battery for a couple of minutes, that SHOULD reset the check engine light and clear any codes set by diagnosing and or repairs you have done in the past. Then if the check engine light comes on again. You shouldn't have any additional codes to confuse you. Hope this helps.