Circuit/System Verification

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

Ignition - On / Vehicle - In Service Mode
Verify DTC P0449 is not set.
- If DTC P0449 is set
  Refer to: Diagnostic Trouble Code (DTC) List - Vehicle .
- Go to next step: If DTC P0449 is not set
Ignition/Vehicle - Off
Remove the component: Fuel Tank Filler Cap or Install the special tool: GE-41415-60 Engine Induction System Leak Test Adapter/Capless Fuel Fill Adapter - Capless Type Fuel Fill
Verify the scan tool parameter: Fuel Tank Pressure Sensor = Between: 1.3 to 1.7 V
- If not between 1.3 and 1.7 V
  Refer to: DTC P0451-P0454 .
- Go to next step: If between 1.3 and 1.7 V
Install the component: Fuel Tank Filler Cap or Remove the special tool: GE-41415-60 Engine Induction System Leak Test Adapter/Capless Fuel Fill Adapter - Capless Type Fuel Fill
Engine - Idling - At normal operating temperature
Perform the scan tool function: EVAP Purge/Seal EVAP Purge Solenoid Valve - 50% - Perform the action while monitoring the parameter: Fuel Tank Pressure Sensor
Verify the scan tool parameter: Fuel Tank Pressure Sensor = Less than 2.5 V
- If 2.5 V or greater
  Refer to: Circuit/System Testing
- Go to next step: If less than 2.5 V
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.
- If the DTC sets
  Refer to Circuit System Testing.
- Go to next step: If the DTC does not set
All OK.