How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Dan Your Own Question
Dan
Dan, Technician
Category: Buick
Satisfied Customers: 23587
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
17871496
Type Your Buick Question Here...
Dan is online now
A new question is answered every 9 seconds

2004 Buick LeSabre the yellow check engine light is on. read

Customer Question

2004 Buick LeSabre
the yellow check engine light is on.
read codes, p0446.
replaced gas cap with new gm delco part, cleared codes, 3 days later CEL on, same p0446 code.
replaced the evap vent valve at just to the rear of the evap canister with a gm Delco part, cleared codes, 4 days later CEL on, same p0446 code.
Please help.
Mike
Submitted: 4 months ago.
Category: Buick
Expert:  Dan replied 4 months ago.

Hello, my name is***** common things to cause this code is fuel cap, vent solenoid, or purge solenoid. But a leak anywhere in system can cause the code. At this point I think you are better off paying a shop to do the smoke test otherwise that would be next step after purge solenoid. Let me know if you have more questions, thanks.

Customer: replied 4 months ago.
Good to meet you Dan. What test should i do first? or what part should i replace first?
Expert:  Dan replied 4 months ago.

I would replace the purge solenoid but if problem still happens after that you will need to have smoke test done. Let me know if you have more questions, thanks.

Customer: replied 4 months ago.
Ok. I replaced the evaporative purge solenoid, cleared codes. 3 days later the yellow check engine came back on with p0446. I had the evaporative system smoke tested and had zero leaks. Please advise.
Mike
Expert:  Dan replied 4 months ago.

The fuel tank pressure sensor is what computer uses to find leaks so if they are sure there are no leaks that means the fuel tank pressure sensor has failed. Let me know if you have more questions, thanks.

Customer: replied 4 months ago.
Where is the tank pressure sensor located?
Expert:  Dan replied 4 months ago.

Here is a picture with replacement instructions.

-

https://www.dropbox.com/s/069eb1nesrm6gig/ftpsrs.pdf?dl=0

Customer: replied 4 months ago.
Can i scan the system with a tech 2 or similar and get readings for the tank pressure sensor?
Is there a trouble tree diagnostic page from the service manual that I can follow for code p0446?
Customer: replied 3 months ago.
Can i scan the system with a tech 2 or similar and get readings for the tank pressure sensor? Is there a trouble tree diagnosis page from the service manual that i can follow for code p0446? Is there a diagnostic aids section for p0446 in the service manual i can follow?