Location of fuel vapor leak detection pump 2004 jeep wrangler

is this a double post, i just posted a huge full answer
just a while ago, on gc.
for same pressure..
the pump check balls bad,or fuelpumpreg inside.
or the injectors leak
last poster too, said awhile, 1s, 1min, 1hr what is while>
spec. is 1/2 min leak down or longer.
so>? but keyon 4 times, is fail

unplug injectors, (elect) is pressure 49 +-5 psi? and holds.
now, bingo.
leak down fails now.
yes the filers are all in tank
yes, the injectors can leak

un connect fuel rail hose, to rail block it.
hold pressure now
yes, bad leaking injector
no,, pump assy bad. assembly, why takes bench tests.

Here is the definition.
You'll need a shop manual for the procedures.

P1494 JEEP Description The Evaporative emissions system is designed to prevent the escape of fuel vapors from the fuel system. Leaks in the system, can allow vapors to escape into the atmosphere. The leak detection system tests for EVAP system leaks and blockage.


During the self-diagnostics, the Powertrain Control Module (PCM) first checks the Leak Detection Pump (LDP) for electrical and mechanical faults. If the first checks pass, the PCM then uses the LD pump to seal the vent valve and pump air into the system to pressurize it. If a leak is present, the PCM will continue pumping the LDP to replace the air that leaks out. The PCM determines the size of the leak based on how fast/long it must pump the LDP as it tries to maintain pressure in the system.
Read more: http://engine-codes.com/p1494_jeep.html#ixzz2JDPIwqxm

P1494 code is a leak detection pump switch or mechanical fault, leak detection pump switch does not respond to input. The leak detection pump (if equipped) is located under the air filter housing on models through 2001. Check if the vapor and vacuum lines are securely connected to the leak detection pump or a diagonstic trouble code my be set like this. The leak detection pump switch may be bad and need replaced.

Could be the P0445 - Evaporative Emission Control System Purge Control Valve Circuit Shorted
The EVAP canister purge volume control solenoid valve uses a ON/OFF duty to control the flow rate of fuel vapor from the EVAP canister. The EVAP canister purge volume control solenoid valve is moved by ON/OFF pulses from the ECM. The longer the ON pulse, the greater the amount of fuel vapor that will flow through the valve.

Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)

Possible causes
- Damage harness or connectors to the Purge Control Valve
- The valve circuit is open or shorted
- EVAP canister purge volume control solenoid valve may be faulty

When is the code detected?
- An excessively high voltage signal is sent to ECM through the valve

Try to remember this code number for additional details. Hope this helps, keep us updated.

Vent tube runs parallel with filler tube, blow it out with compressed air.

vacuum leak. you should have a leak detection pump. locate this in the rear and check hoses. sometimes the hoses split on jeeps. easy cheap fix if you can find it.

It's very possible that your fuel tank vent hose is bloked or kinked.

The evap system ( fuel vapor recovery system ) , if there is a leaky hose, can let fumes out that can be detected in the cab. If you "top off" the fuel at the pump you can spill fuel into the charcoal canister meant for fuel vapors only. the vapor recovery system is behind the left rear tire.

Usually if there is a hose leak a check engine light will come on.

If you TOP OFF, don't. If you don't, good. Hope this helps.

most likely the pressure sensor in the fuel tank for the evap system is defective.

THE SOLINOID VALVE IS ONLY PART OF THE SYSTEM YOU MAY HAVE A LDP (LEAK DETECTION PUMP) PROBLEM INTERNAL LEAKS ARE HARD TO DIAG YOU MAY WANT TO BRING TO A DEALER.