Check engine light

Good afternoon.

First thing is we need the code to help you narrow the area of failure.

No to that eight times thing. That is not true.

My suggestion is to stop resetting and throwing parts with no results. lets get to the root cause of the failure.

Roy

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

https://www.2carpros.com/articles/check-engine-light-clear-codes

There are too many EVAP codes to guess. Get it checked again for the code and get back to us with the code numbers.

Roy

Okay, in most cases the vent valve is the failure but needs to be checked to confirm.

Roy

DTC P0443 or P0449

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. See: Vehicle > Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P0443
- Evaporative Emission (EVAP) Purge Solenoid Control Circuit

DTC P0449
- Evaporative Emission (EVAP) Vent Solenoid Control Circuit

Diagnostic Fault Information

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Circuit/System Description

An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The engine control module (ECM) grounds the EVAP canister purge solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. The EVAP canister purge solenoid valve is pulse width modulated (PWM). A scan tool will display the amount of ON time as a percentage.

Battery voltage is supplied to the EVAP canister solenoid valve. The ECM grounds the EVAP canister vent solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. A scan tool will display the commanded state of the EVAP canister vent solenoid valve as ON or OFF.

Conditions for Running the DTC

* The ignition is ON.
* The system voltage is between 9-18 volts.
* DTCs P0443 and P0449 run continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for a minimum of 5 seconds.

Action Taken When the DTC Sets

* DTC P0443 is a Type B DTC.
* DTC P0449 is a Type A DTC.

Conditions for Clearing the MIL/DTC

* DTC P0443 is a Type B DTC.
* DTC P0449 is a Type A DTC.

Circuit/System Verification

P0443
1. Ignition ON, engine OFF, you should hear a clicking sound when the EVAP canister purge solenoid valve is commanded to 50 percent with a scan tool. The clicking sound should stop when the EVAP canister purge solenoid valve is commanded to 0 percent. The rate at which the valve cycles should increase when the commanded state is increased, and decrease when the commanded state is decreased.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

P0449
1. Ignition ON, engine OFF, command the EVAP vent solenoid ON and OFF with a scan tool.
2. Listen for a click when the valve operates. Verify that both the ON, and the OFF states are commanded.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EVAP canister purge or vent solenoid valve.
2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal A and ground.

If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test or replace the EVAP canister purge solenoid.

3. Connect a test lamp between the voltage supply circuit terminal A and the control circuit terminal B.
4. Command the EVAP canister purge solenoid valve to 50 percent with a scan tool, or the EVAP canister vent solenoid valve ON and OFF. The test lamp should respond to the command.

If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, replace the appropriate solenoid valve.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. See: A L L Diagnostic Trouble Codes ( DTC ) > Verification Tests

* Evaporative Emission Canister Purge Solenoid Valve Replacement
* Evaporative Emission Canister Vent Solenoid Valve Replacement (15 Regular Cab) Evaporative Emission Canister Vent Solenoid Valve Replacement (15 Ext/Crew Cab) Evaporative Emission Canister Vent Solenoid Valve Replacement (25 Ext/Crew Cab w/6 Ft Bed) Evaporative Emission Canister Vent Solenoid Valve Replacement (15/25 Reg/Ext/Crew Cab w/8 Ft Bed) Evaporative Emission Canister Vent Solenoid Valve Replacement (35 Reg/Ext/Crew Cab w/8Ft Bed)

P0449
Item Description
Symptom/DTC P0449
Descriptor
Probable Causes
Engine Control Module (ECM)
Evaporative Emission (EVAP) Vent Solenoid
K20 Engine Control Module (ECM)

The valve is a normally open valve. It is commanded closed when the EVAP system is doing its internal test. The valve is not closing causing a large leak.

Roy

No, it is part of the vent valve. You can get it at a parts store.

https://www.rockauto.com/en/catalog/gmc,2008,sierra+1500,5.3l+v8,1441178,exhaust+&+emission,vapor+canister+vent+valve+/+solenoid,16992

It has two ports. One hose goes to the canister and one to outside air.

There is a two wire connector to the solenoid.

Roy