Hey everyone, I'm new to working on Chevrolet trucks and I recently purchased a 2004 Chevrolet blazer 4dr for a great price. The truck is in great shape with 180,xxx miles and when I bought it the dash was clear from any check engine lights. After I bought the truck, I drove it 40miles home and not until after I went to take it to the car wash, the check engine light came on with the code P0446. Mind you that my fuel gauge doesn't work at all and I have to fill the truck up full tank and reset the miles to know how much fuel I have in it. I don't believe that could be causing the code but I also have P0452 & P0453 with my P0446 code. I seen this diagram and am a bit confused on where to start looking on replacing the necessary parts. I have emissions coming up in the next two weeks, I really need help removing this light out to pass the truck. Thanks

Diagram link: http://i11.photobucket.com/albums/a1...446_DC1of3.gif

https://blazerforum.com/forum/diagno...plained-35143/

 

You can read the code explanations in Diagnostic Trouble Codes (DTCs).

 

Thank you for the link, I already checked that out. I wanted to know if anyone else had this happen to them so I can check out the main components that I need to look at. The light came on when I tried over filling my blazer. I wonder if that has anything to do with my check engine light?

 

The EVAP system monitor uses fuel level data during its tests. If the fuel gauge doesn't work, you'll get EVAP codes when the monitor tries to run. Fix the fuel gauge and perform a General Motors Driving Cycle


CONDITIONS FOR RUNNING THE DTC

* No active MAP sensor DTCs
* No active TP sensor DTCs
* No active VS sensor DTCs
* No active O2 sensor DTCs
* No active ECT sensor DTCs
* No active IAT sensor DTCs
* DTC P0125 not active
* The fuel level is more that 12.5 percent but less than 87 percent .
* The system voltage is between 10-17 volts .
* The ECT is between 4°-30°C (39°-86°F) .
* The IAT is between 4°-30°C (39°F-86°F) .
* The cold start temperature difference (ECT minus IAT) is less than 1.5°C when the IAT is more than the ECT or

8°C when the ECT is more than the IAT

* The BARO is more than 72 kPa .
* The change in fuel tank vacuum is less than 0.6 inches of H2O, or the change in fuel level is less than 8 percent .
* The fuel tank vacuum level remains above a calibrated value for a specified number of seconds.

 

What does the General Motors driving cycle do? And do you think because my fuel gauge no longer works is the reason for my check engine light?

 

The PCM continuously monitors several components and circuits for problems. Other components and circuits are not continuously monitored while driving. Performing the drive cycle forces all of the monitors to run and complete their tests. If the entire drive cycle is performed exactly as outlined, and the check engine light remains off, there were no problems detected and all of the monitors ran, completed, and passed their tests. Most of the monitors will run and complete their test during normal driving, others may take days, weeks, or even months to run and complete.

The steps do not have to be done in order, and you don't have to run every step, but when you do perform a step, it must be performed exactly as outlined or the test will not run and complete. After you perform the drive cycle, you can check "Monitor Status" on a scan tool to make sure they have all completed.

 

Hey everyone, just a quick update! I just finished replacing a new fuel lever and fuel pressure sensor on my tank. Check engine light for P0452 & P0446 are now gone. And my fuel gauge now works! Hopefully this can be helpful to others. I still need to drive the blazer around more, some of the stuff is still reading not ready. I will keep everyone posted, thanks.

 

Thank for posting back with the "fix"

To answer your question in post #5.... yes, if the fuel level indicating system is inoperative, the EVAP monitor will not run. The EVAP monitor will only run when fuel level is between 15% & 85%.

 

No problem, I noticed alot of threads people create and don't even give the outcome that solved there problem. But anyways, I have 6 monitors ok and ready, 4 monitors evap, a/c, heater, and something else not supported. And I just have the evap system monitor that is still incomplete. That's my last moniter that needs to be ready and I can redue my emission test again. I tried the gm driving cycle, and I failed at doing it. It's hard without a dyno machine to just roll the wheels, inside of doing it on the street. But anyways, so far I put in 80miles after last battery reset. I'll update again tomorrow!