Circuit/System Description
WARNING: This page is about a different car, the 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path that would cause excess amounts of vacuum to be developed in the EVAP system. With the purge valve open and the canister vent valve open, if the EVAP system vacuum goes above a calibrated threshold, the test will fail.
| FTP Sensor Signal Voltage | Fuel Tank Pressure |
|---|---|
| Low, Approximately 1.5 V or less | Positive Pressure |
| High, Approximately 1.5 V or more | Negative Pressure/Vacuum |