I am getting a PO455
P0455 (M) Evap Leak Monitor Large Leak Detected A large leak has been detected in the evaporative system.


and

P0442 (M) Evap Leak Monitor Medium Leak Detected A small leak has been detected in the evaporative system.

Can someone give me plain english as to what its telling me.

2001 TJ 125000 miles. Stock everything except the TB spacer and the large K&N racing filter.

Also what is better magnaflow or flowmaster exhaust. Not the loudest just better.

Thanks
Carlos

I think its telling you that you've got a vaccum leak somewhere between the engine and the back corner of your jeep by the gas tank. I had that this summer.

I just started showing P0456. Out at the All-4-Fun a friend bought a code reader and we hooked it up to my TJ. It had a function that allowed us to "clear" that error code. At first we thought it wasn't working, but someone else suggested that since the error or problem still existed, it couldn't clear it. Not problem for me, I'd driven 1500 miles getting there, plus 3 or 4 days of trail riding.

So I did what I usually do when the jeep is running just fine, I ignored it. Somewhere about half way across Kansas the error code just wasn't there when I checked my dash. I guess the line was self sealing...or something.

I'm firmly convinced that having the computer toss out codes is just an income generating scheme for the dealers. Makes you take it back and earns them some repair dollars, much like them squirting oil on the underside of your crankcase, or cutting your fan belts and telling you they need to be replaced.

The classic fix for the vaccum leak is to pop the hood with the engine running and then spraying WD40 along the lines around the engine and back toward the fuel tank. When you hear the engine change tone, its probably where the leak is. Often with older vehicles its the rubber that is cracked at a bend. OR its breaking right at a connector. Once you find it, you can cover it with your finger and make the engine change RPM.

I see from your post that you're in Texas. That translates into hot and dry, the enemy of rubber tubing. Someplace you've probably got a leak and need to find and replace that piece of hose.

Dick,

Thanks, I will look for a leak.

Carlos

Do you know what emission package you have on your TJ? CA, 50 state etc? The first thing I would check is your gas cap. Make sure its seating tight. After that check your vacuum lines. The rubber lines get brittle after time and crack at the ends. I believe the bulk of your emission system is over your driver fender between the brake master cylinder and the washer reservoir. Lots of little hoses there waiting to crack.