Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit/System Testing: Restriction
2008 Pontiac Grand Prix BaseSECTION Restriction
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
With the engine running, the EVAP canister vent solenoid valve open, and the EVAP canister purge solenoid valve commanded to 100 percent, the fuel tank vacuum should not increase to more than 11 inches H2O.
- If the fuel tank vacuum is greater than the specified value, isolate the restriction by disconnecting one component at a time while the EVAP canister purge solenoid valve is commanded to 100 percent and the vent valve is open.
FTP Sensor
- Ignition ON and fuel cap removed, verify that the FTP sensor parameter is between 1.3-1.7 volts.
- If the FTP sensor parameter is not within the specified range, test the FTP low reference circuit for an open or high resistance. If the circuit tests normal, replace the FTP sensor.
- With the GE-41415-50 , connect the J 41413-200 to the fuel filler neck.
- Start the engine.
- Allow the engine to idle.
- Use the Purge/Seal function to seal the system with a scan tool.
- Command the EVAP canister purge solenoid valve to 20 percent.
- Observe the vacuum/pressure gage on the J 41413-200 and the FTP parameter on the scan tool.
- Verify that the vacuum increases to the abort limit on the scan tool or more than 3.2 volts, and the value is similar between the scan tool and the vacuum/pressure gage on the J 41413-200
.
- If the values are not similar, or the voltage is not within the specified range, replace the FTP sensor.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.