Grand Prix 3.8 SE 1441 DTC

[Rammer]

I got my '97 Pontiac back from the body shop(replacing rocker panels) and within 1 Day I started getting this code along with an EGR pintle position and a couple for the oil level and change oil light circuits. Car runs great.

 

The EGR, I've gotten a few times before and always cleared itself. I think the valve was sticking sometimes. I bit the bullet ($144) and I replaced the valve, passes the test now.

 

 

 

I found the problem with the light circuit faults. A mouse chewed the insulation of the wires for those circiuts at the PCM and might have been grounding them. Wires for the EVAP system were not effected. GM's infinate wisdom has the PCM and air filter mounted in the same box with air being pulled in from the fenderwell pass the PCM to the filter. That's how the mouse got into the PCM part of the box.

 

 

I started checking the EVAP system and the only thing that tells the PCM whether its purging or not is a vaccum switch (normally closed) between the canister and the purge solinoid. Am I correct?

 

I found the it uses 12 volt so I probed the wires on the switch and have voltage to the switch and voltage after the switch, when there's no Vaccum.

 

With vaccum, the switch does open. With the engine idleing, the voltage pulsates with the modulation of the purge solinoid. As the engine speeds up the voltage will drop out completely.

 

Sometimes it passes it's test, most of the time it doesn't. Will this pulsating voltage be the problem, maybe a small leak in one of the canister's lines and not enough vaccum to turn the voltage completely off at idle? Or is this normal operation?

 

I also probed the wire from the switch at PCM checking for a bad wire, wiring checks out good. The only other thing I can think of is the PCM is damaged from the d**n mouse chewing the insulation and maybe shorting out something.

 

Sorry for this being so long, but I wanted to give you all the information I could.

Thanks

[dougmac]

I got my '97 Pontiac

 

<{POST_SNAPBACK}>

 

 

What model of Pontiac? errr ..... never mind I guess I could read it in the title.....

[dougmac]

I found it…. P1441

 

It is telling you that Fuel Tank Pressure (FTP) sensor is detecting a vacuum when the purge valve is not energized and should be closed.

 

So you ether have vacuum leaking past the purge valve or you have the FTP detecting vacuum that is not there.

 

If it is intermittent, you may not be able to catch it in the act. You can check the purge valve by checking the vacuum on the purge circuit with the purge valve disconnected. The vacuum should not raise with the valve de-energized (closed). If you have vacuum present with the valve de-energized, the purge valve is leaking.

 

I would lean towards the purge valve leaking as the most likely problem.

 

Good Luck,

Doug

[Rammer]

The 97's have a vaccum monitoring switch between the canister and purge valve and that checks out OK. Purge valve is OK also. I'm not sure if it has a fuel tank pressure switch, this has the NON-Enhanced evap system. I'll look into a fuel tank pressure switch to check. Thanks