Diagnose check engine light Hyundai Elantra with stored diagnostic trouble code p0442 small evaporative emission system leak.
On this vehicle I was unable to find any On this vehicle I was unable to find any visible leaks with a smoke machine but was able to find a possible cause and in this video I show you how to easily remedy that thanks for watching be sure to subscribe to the flat rate mechanic for more money-saving auto repair videos.
1. Monitor the fuel tank pressure sensor voltage either with the scanner or using at voltmeter (Green/Orange wire pin 33 at the Electronic Control Module). The fuel tank pressure sensor should have approximately 5 volts on the Red wire (pin 44) and a ground on the Blue/Black wire. With atmospheric pressure on the system, the voltage on the Green/Orange wire should be near 2.5 volts.
2. Next ground the canister close valve Blue/Black wire, this should close the valve and seal the system.
3. With the engine idling, locate the purge control valve (under the throttle body, inline of the vacuum hose) and tap the Yellow/Orange wire to ground while watching the fuel tank pressure sensor voltage. Bring the voltage down to near 1 volt and stop tapping the ground. The voltage should hold if there are no leaks. If the voltage starts to rise pinch off the hose between the canister and the fuel tank. If the voltage stops rising the leak is in the canister, canister close valve or hoses.
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