OBD II CODE P1450: How to fix

[kjnoldy]

Had to put a new tranny in my 1997 F150 XLT Lariat 4x4 5.4 liter engine about 3 weeks ago and now have gotten the check engine light. Took it to autozone and code 1450 was the only code listed. They said it was was a vacuum problem, but when I checked the code at a web site it is listed as a secondary air injector system circuit shot to B+. My question is which is correct and how to repair? Thanks, kjnoldy 1984 F250 1996 Lincoln 2000 Stang

[Racerguy]

Hi kjoldy and welcome to FTE

Here is what the Ford manual says about a P1450.....


Continuous Memory Diagnostic Trouble Code (DTC) P0446 or P1450 indicates that Self-Test has detected the Evaporative Emission Control System has excessive fuel tank vacuum. Also, a DTC P0446 indicates a vent control malfunction.

Possible causes:

EVAP canister purge outlet tube (EVAP canister purge valve to EVAP canister) blockages or kinks.
EVAP canister tube (fuel tank to EVAP canister) blockages or kinks.
Fuel vapor elbow on EVAP canister contaminated.
Restricted EVAP canister.
Canister vent (CV) solenoid stuck closed (partially or fully).
Plugged or contaminated CV solenoid filter.
EVAP canister purge valve stuck open.
Fuel filler cap stuck closed (no vacuum relief).
VREF circuit open in fuel tank pressure (FTP) sensor.
Damaged FTP sensor.

The common problems I've seen that cause this code are mud in the CV solenoid and related parts, and wiring to the CV ripped apart. The parts I am talking about are in front of the spare tire, above and behind the rear diff.

[kjnoldy]

Thanks, I'll check them out and let you know the results.
kjnoldy

[kjnoldy]

Racerguy,
I took removed the cannister rack and reseated cv vent solenoid connection. There was some dirt up there. Blew air through cv vent solenoid, no restrictions. Blew air through cannisters, no restrictions. Blew air through gas tank vent tube, no restrictions.

When I went to blow air through line that "Y"s off into two lines there seems to be some restriction, it seemed to take a little more
force. My gas tank is full so I'm wondering if that had anything to do with it.

When I was reassembling tubing I am not sure if I connected the tubing to the cannister correctly. Does the line that "Y"s off into two lines connect to the CV vent solenoid or the plain elbow?

I erased the code by disconnecting the battery. I then followed the restart procedure. I hope the code does not reoccur.

kjnoldy

[Racerguy]

Without actually looking at a truck I cant remember exactly how the lines went but they usually fit better the correct way.
This is the best picture I have. Maybe it will help......

[kjnoldy]

Thanks Racerguy, I'll double check it. I drove the truck about 40 miles today. No lights yet, but there is a strange hum that tends to occur after the truck has been driven awhile. Truck is driving smoothly, but I wonder of any of the solenoids or valves are bad.

[kjnoldy]

Racerguy, No check engine lights all this week. Drove truck everyday. I hope this means the problem was fixed. Thanks again Racerguy.

[Racerguy]

Youre welcome
I hope the light stays out for you.
In case you're wondering, I edited your email address out of your posts. Apparently in the past spammers have got addresses from posts.

[kjnoldy]

I won't put my email in anymore. Thanks for the tip.
kjnoldy

[Leddedhed Evans]

I'm having some of the same issues.Just changed plugs and all codes cleared but P1450.If the issue is vacuum displacement in the tank,would this cause stumble or negative response during acceleration?At first the plug change increased performance but after 500 miles it was as if plugs were never changed.I removed the fuel cap and still no change(per vacuum problem).
I would be thankful for any help since the dealership has changed and fixed it 5not fixed after $700 and multiple sensor changes).