Chevrolet Colorado & GMC Canyon Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
256 Posts
Discussion Starter #1
Yes I read all the posts but none had the same two codes as mine and that's why I'm posting this.

So after my mudding catastrophe, I replaced the radiator and cooling fan and it drove home fine but the cel came on and threw a P0446 code (evaporative emission control system vent control circuit malfunction). The next day I took it to the mechanic to get the front main seal and transfer case extension seal replaced cause they were leaking, on the way the truck starts idling rough and took a few seconds to accelerate from a stop so I get it scanned and it throws a P0301 (cylinder 1 misfire). The exhaust which is stock sounds kinda muffled and smells like it's running rich. Any chance the two cel codes are causing one another? Truck is an 06 3.5L with 90,500 miles
 

Attachments

·
Premium Member
Joined
·
2,761 Posts
The DTCs aren't related. The P0446 indicates a blockage in the Evap Vent System. Most likely due to the canister/vent solenoid (located above the spare tire) being submerged. The P0301 could be a bad coil or plug or wiring. The suggested first course of action for that would be to swap the coil with another cylinder. If you swapped it with #3 and a code P0303 showed up, it would indicate a bad coil.

The P0446 shouldn't cause a change in the way the engine runs.
 

·
Registered
Joined
·
256 Posts
Discussion Starter #3
It's at the mechanics right now and he said he was going to check it out but suggested that I do a tune up die to the mileage and not knowing what the previous owner had done to it. I'm just paranoid with all the posts referring to a bad head but the only way to check that is with a leak down test. For the P0446 your idea makes sense because t was submerged for about 10 minutes when I got stuck
 

·
Registered
Joined
·
256 Posts
Discussion Starter #4
The DTCs aren't related. The P0446 indicates a blockage in the Evap Vent System. Most likely due to the canister/vent solenoid (located above the spare tire) being submerged. The P0301 could be a bad coil or plug or wiring. The suggested first course of action for that would be to swap the coil with another cylinder. If you swapped it with #3 and a code P0303 showed up, it would indicate a bad coil.

The P0446 shouldn't cause a change in the way the engine runs.
So I got the truck back yesterday and he said there was a little water on the coil so he dried t and replaced all the plugs. Seems to be running fine but my inspection is expired and I went to get t done but it's saying that there's two incomplete monitors but the check engine light is not on? I believe they were the 2nd catalytic converter and something with the evap. Is there a certain number of miles I have to drive to reset everything
 

·
Premium Member
Joined
·
2,761 Posts
What did you (or the mechanic) do to correct the P0446 DTC? If the mechanic turned off the "check engine" light with a scan tool, it will come back when the ECM tests the Evap System and it fails. You will probably have to get a scan to determine the DTC for the catalytic converter. The catalytic converter problem could be because the O2 sensor connector/wiring went swimming.
 

·
Registered
Joined
·
256 Posts
Discussion Starter #6
What did you (or the mechanic) do to correct the P0446 DTC? If the mechanic turned off the "check engine" light with a scan tool, it will come back when the ECM tests the Evap System and it fails. You will probably have to get a scan to determine the DTC for the catalytic converter. The catalytic converter problem could be because the O2 sensor connector/wiring went swimming.
I haven't done anything nor the mechanic to fix the P0446. I'm sure he cleared the codes but I've put about 60 miles on it since getting it back and the check engine light hasn't come back on but I'll use my managers scanner or go to O'Reillys and see if it pulls anything. There's still some dried up mud on the O2 sensor so I'll clean it and see what happens
 

·
Registered
Joined
·
256 Posts
Discussion Starter #7
What did you (or the mechanic) do to correct the P0446 DTC? If the mechanic turned off the "check engine" light with a scan tool, it will come back when the ECM tests the Evap System and it fails. You will probably have to get a scan to determine the DTC for the catalytic converter. The catalytic converter problem could be because the O2 sensor connector/wiring went swimming.
I haven't done anything nor the mechanic to fix the P0446. I'm sure he cleared the codes but I've put about 60 miles on it since getting it back and the check engine light hasn't come back on but I'll use my managers scanner or go to O'Reillys and see if it pulls anything. There's still some dried up mud on the O2 sensor so I'll clean it and see what happens
 
1 - 7 of 7 Posts
Top