DTC #P0446 for 01 and 03 trucks

[Victory Red]

I have an '01 factory manual but now have an '03 truck. Are most of the DTCs the same from one year to the next. I keep getting a P0446 code on my '03 Sierra. It has been cleared twice and still comes back. Finally took the truck to the "stealer" and they spent all day trying to find it. They replaced the Fuel Vapor Pressure Sensor (part # 9377680) because they said it tested "out of range". According to my manual a P0446 code is for a EVAP cannister vent blockage. After they changed the sensor the truck was fine for one whole day, then it set the code again. It's going back to the dealer on Monday so they can "try" again. My manual doesn't even show a Fuel Vapor Pressure Sensor. Must be something new for the '03s. From what I read, it sounded like the EVAP cannister vent control relay, or possibly just the vent hose itself is clogged. I couldn't find where the vent hose comes out. It looks like it goes up and over the fuel tank. I'm thinking the hose has some dirt or something in the end of it. You would think they would check something as simple as that first, before doing a lot of diagnostic testing.

 

Anyone had this code set on an '03? And NO, it's not the gas cap! I have a GM factory locking cap that I got from GM Parts Direct, and it is ALWAYS installed with the clicks and is tight. I even cleared the code once and reinstalled the original gas cap that came with the truck. It still set the P0446 code. The truck runs fine, and there are no other problems other than the light being on all the time.

 

I'll post back Monday after I see what the dealer has to say this time.

[frdfandc]

I had the same code approx 4 months ago. I scanned the PCM at work. Cleared the code. Light came back on. Rescanned the PCM. Same code. Took it to the dealer. They supposedly installed a new Evap sensor (don't have the exact definition on the receipt). Light came back on a few days later. Took it back in. Ended up being the same code again The replaced the Evap canister and bracket. Supposed to be an updated part.

 

Part number for the Evap Cannister is #15175906 and the bracket is #15175907.

 

 

Hope this helps.

[Victory Red]

Well, I just got back from the dealer. They changed out the EVAP cannister vent solenoid valve (#15759044). No explaination as to why they came to that conclusion, but it seems to be working so far. If I can go a week with no light, then I'll consider it a complete repair. BTW, it was the same P0446 code this time too. Lets hope it doesn't set the same code a third time. I may not be responsible for my actions....

[farfree2]

Hello all, I have the same problem. Can anyone tell me where the canister is located on the truck? Is it easy to get to or no? Also, do you need to purchase a new bracket for the canister or can you use the existing one?

 

All your help would be greatly appreciated.

 

Thanks

[NothinButBowTies]

Victory Red -

Can you give me the part number for the locking gas cap? I have always wanted the locking feature....you never know when some kid gets the bright idea to pee in your tank