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.
Small Leak Test
If the large leak test passes the PCM will continue to monitor the fuel tank pressure (FTP) sensor signal in order to determine if there is vacuum decay. A slight increase or rise in pressure indicates there is a small leak in the evaporative emission system. The EVAP control system is required to detect evaporative emission fuel system leaks as small as 0.020" (0.5 mm) between the fuel fill cap and the purge valve. If the PCM detects vacuum decay was evident for two consecutive trips, the MIL will illuminate, and DTC P0442 will set.
NO RELATED
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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.