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.
Tank Pressure Control Valve (TPCV) Check
Remove the TPCV from the vehicle. Attach a hose to the fuel tank port of the TPCV and blow through it. A resistance should be felt until enough pressure unseats the diaphragm at which time flow increases.
With a hand pump, apply vacuum (15" Hg. or 51 kPa) to the upper tube (manifold vacuum supply port) of the TPCV. If the diaphragm does not hold vacuum for at least 20 seconds, the diaphragm is leaking, and the TPCV must be replaced.
If the diaphragm holds vacuum, try to blow through the hose connected to the lower tube while vacuum is still being applied. An increased flow of air should be observed. If not, replace the TPCV.
Use the Manual With the Right Hardware
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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.