This code indicates that a vacuum was detected while the system was in the non purge state. Initially I did not know much about this and started reading some posts on the internet. All I knew is that my check engine light did not go out.
When the car is parked the fumes are actually stored in the vapor canister. This is made this way to prevent them from escaping into the atmosphere where they cause pollution. When the car is started the fumes are fed into the intake manafold where they are eventually burned. The car opens a valve that “purges” the canister by introducing a vacuum and sucking out the air from the canister. The vacuum is initiated by a “purge solenoid valve”. When 12v is applied to the terminals of this valve by the car’s computer the valve opens up and allows the air to escape into the intake manifold. A lot of times this valve goes bad and allows air to pass into the intake manafold all the time. The car also has a vacuum monitoring switch mounted close to the valve. The job of this switch is to monitor for a vacuum. When air is passing by the valve all the time the monitoring switch will detect a vacuum and alert the computer. The computer will issue a DTC p1441 code.
I have a 1996 Pontiac Firebird LT1.
I started replacing my EVAP purge solenoid and the vacuum monitoring switch, and Clearing the DTC code… No luck.
I had replaced my canister as well as the check valve connected to it. These parts are located on the left side quarter-panel at the back of the car behind the wheel. I also had the mechanic make sure the hose was clear of any charcoal by disconnecting it from everything and blowing air into it. I replaced part 11 and 7 seen in the diagram. The gas cap was also replaced. No luck… Now that I think about it replacing the GAS cap did not make any sense at all. The trouble code says that it is detecting a vacuum during a non-purge state. That means that there is a vaccume in the gas tank and that means the gas cap is NOT leaking.
I went crazy replacing anything and everything EVAP related in my car till I ran out of parts to replace. Went back TEST each part again and I found the defective valve.
Replaced the Purge solenoid valve for the 2nd time. And Problem SOLVED!!! It looks like the dealership send me a defective part or the part went bad soon after I got it. I am wondering what would cause the valve to go bad? Is compression breaking to blame??? I stopped doing that now. Hopefully I don’t have to see this dreadful code again.
To test the purge solenoid valve:
The purge solenoid valve should not permit flow when no voltage is applied to its terminal. As soon as 12v input is applied it should be free flowing. I used an instrument similar to this to test the system.