pet1

Hi again. I just had a tune up. New fuel filter, plugs, air filter and coil pack. Five days later p1494 pops up. EVAP leak. After poking around the engine, couldn't find any disconnected hose/valves. So I went underneath the car and found the newly installed fuel filter with a disconnected hose. I popped them back together and put some tape for safer measure. Would this have caused the code to pop up? If so would the check engine light turn itself off or would it have to be reset? And, can it be done just by disconnecting the negative from the battery terminal? It's safe to say I'm not going back to this mechanic as he was giving me the run around saying it wasn't him. Well.. I know I didn't install the fuel filter...

ZJMAX

Yes that hose would cause that. It will clear itself after a few drive cycles, you can clear it with a scan tool or buy disconnecting the battery for 30 minutes.

Max

pet1

I'm assuming it takes 200 miles to turn off just like it takes that amount of miles to turn on. I just removed the negative terminal for 5 minutes and the light turned off and was told by a passer by that wouldn't work and the I just removed the indicator light but the code is still present. Thanks for the prompt reply.

dave1123

Either you had it scanned or did the key trick to find the p-code, so do it again to see if it's still there. Autozone and others will read the codes for you, but by law they aren't allowed to clear them without doing the work. If you have access to a scanner, you can clear it yourself. I paid close to $100 for mine and it's the best tool I ever bought. Not only does it give me the codes, but it explains them.

pet1

Well, autozone cleared for me last week when it happened initially. And popped up after 200 miles. I left the negative off for 45 minutes and reconnected it. The light is now off. Hopefully after 200 miles or so it doesn't pop back. What is the key trick btw? Thanks again.

dave1123

It depends on what you've got. The codes will either be a flash code of the CEL light on jeeps up until 98, or a "p" code displayed in the odometer on later ones. Turn the key on until the warning lights light, then off, on, off,then on and wait. When it's done with the codes, if any, on later ones the word "done" will appear or a code 55 on earlier models. You have to count the flashes on the earlier ones and that can get confusing, but you can do it again to be sure. Have a pen and paper handy to write them down if there's more than one.

My book says a P1494 is "Leak detection pump switch not responding to input."

It's very important that you let us know your year, model, and engine size when you ask questions.

pet1

Thanks. Gonna check this out right now actually. It's a 02, Grand Cherokee Laredo, 4x4, 4.0

So it just reported done in the odometer. Nothing else preceded it.

Cherryokee

If the code repeats then do a smoke-test or hiss-test (in a very quiet eviro). My '99 XJ with a 4.0 had a cracked, not broken, nipple at the air purge can (under the car, driver side, rear passenger seat area, behind a shield).

One other possible source for that code is a defective or poorly seated gas cap (cap vent failure). A good indicator for that is when you unscrew the gas cap and you hear a whooshing sound - like a sudden short vacuum sound.

dave1123

So the codes have been cleared and none returned. Good for now. Let's see of it returns. Either way, a code 1494 is nothing to be concerned about until you need to pass inspection. It's not going to effect the way it runs. It has to do with the fuel vapor recovery and tank venting system. If you feel you need to fix now, that's okay too, but after reconnecting that hose, it might not return.

pet1

Yes hopefully it was the disconnected hose and the light stays off. I'll update in 200 miles or so. Thanks again.