code P0442A evap small leak


struggle
10-29-2005, 11:09 PM
I am looking for anyone that might have some idea on why this code keeps coming on. It does it intermittently and some times stays off for two months and other times it turns on in two weeks. Gas cap has been replaced with no change. Filler tube clamps are tight. Is there any known problems for this code :banghead:

It is a 2001 Grand Am 2.4L auto. I have checked everything. Short of buying a smoke machine I am up a creek on this one. I have a professional scan tool but on it all I can do is wait for the code to come back. I can not drive it for weeks to freeze frame info on it with the scanner in the car :eek7:

Any help would be great. This has been going on now for two years now with no noticable trend to when it fails :banghead:

GMMerlin
10-30-2005, 08:47 AM
I am looking for anyone that might have some idea on why this code keeps coming on. It does it intermittently and some times stays off for two months and other times it turns on in two weeks. Gas cap has been replaced with no change. Filler tube clamps are tight. Is there any known problems for this code :banghead:

It is a 2001 Grand Am 2.4L auto. I have checked everything. Short of buying a smoke machine I am up a creek on this one. I have a professional scan tool but on it all I can do is wait for the code to come back. I can not drive it for weeks to freeze frame info on it with the scanner in the car :eek7:

Any help would be great. This has been going on now for two years now with no noticable trend to when it fails :banghead:

Proper testing of the EVAP system will lead to the root cause.
The EVAP small leak test applies vacuum to the evaporative emission (EVAP) system and monitors vacuum decay. The powertrain control module (PCM) monitors the fuel tank pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the PCM turns the EVAP canister purge valve ON (open) and the EVAP vent valve ON (closed). This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the PCM turns the purge valve OFF (closed), sealing the system, and monitors the FTP sensor input in order to determine EVAP system vacuum decay. If the system detects a leak larger than a calibrated amount DTC P0442 will set.
The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
inspect for leaks in the following locations:
The EVAP system purge pipe.
The EVAP vapor pipe.
The EVAP vent hose/pipe.

The fuel fill pipe/hose and fuel fill cap.

The EVAP canister.
The EVAP canister vent valve.
The EVAP canister purge valve.
The fuel sender assembly and/or seal.
The FTP sensor seal.
The fill limiter vent valve, pressure relief valve, rollover valves, and fuel tank.

wjbarton
02-01-2006, 01:38 PM
Did you have any success with this P0442? I'm having the same issue, curious...

- WJB

wadedm
03-27-2006, 09:36 AM
I too am having the same problems, what solved yours?

xeroinfinity
03-27-2006, 10:31 AM
take it to a dealer or other Qualified shop to get it diagnosed properly.
That is if you cant find something mentioned above thats loose or broken on or in the Evap system.
My GT had this and it was loose conectors, and bad relays under the hood.
Good Hunting my friends!

Add your comment to this topic!