Circuit/System Testing
WARNING: This page is about a different car, the 2012 GMC Yukon, 2012 Chevrolet Tahoe, and 2012 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Perform the Circuit/System Verification before proceeding with the Circuit/System Testing.
Restriction
- With the engine running, the EVAP vent solenoid valve open, and the purge solenoid valve commanded to 100 %, the fuel tank vacuum should not increase to more than -15 mm Hg (-8 in H2O).
- If greater than the specified value, isolate the restriction by disconnecting one component at a time while the EVAP purge solenoid valve is commanded to 100 % and the vent valve is open.
- Using the scan tool, decrease the canister purge duty cycle from 100 % to 0 %. The vacuum should decrease to near zero.
- If not the specified value, or appears to decrease too slowly, inspect the components in the EVAP vent system for a restriction.
Fuel Tank Pressure Sensor
- Ignition OFF, disconnect the harness connector at the B150 Fuel Tank Pressure Sensor.
- Ignition OFF, all vehicle systems OFF, this may take up to 2 min for all vehicle systems to power down. Test for less than 5 Ω between the low reference circuit terminal and ground.
- If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the B150 Fuel Tank Pressure Sensor.