I have a 200 Cherokee, 4.0L, and have a p0455 code/Evap large leak detected. When I got the code read at Autozone, they gave me a printout of all the possibilities, but the guy said that since I had not filled up my gas in the past few days, that it could not be a loose or bad gascap. I think that that may still be possible. The gascap itself is only like a year old, and came from the dealership, so it is not some aftermarket crap. I also have made sure that somehow the cap did not come loose, which it hadn't. Do any of you think it would be worth it to try replacing the gas cap first, before I try doing other means suggested to correct this problem? Thanks in advance for an advice offered!
This indicates a fuel vapor leak or lack of purge flow in the EVAP control system. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.
Yes, a loose or faulty gas cap can create this code. But also any leak in and around the charcoal canister could do it too. Check the canister and lines in and out. You may (but not always) hear a vacuum noise or smell fuel in the area of the leak. Smoke testing as mentioned before can be helpful if you don't stumble onto the cause.
99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche Without "data", all you have is an opinion!
I had a persistent P0455 code on my 2000 Cherokee Sport (4.0 XJ). I changed the gas cap first and the code stayed. I next took it in for a smoke test -- smoke is pumped through the evap system to check for leaks. There were no leaks. The shop said it's probably the EVAP Leak Detection Pump (LDP), but "we're not sure." I decided not to pay shop prices for a maybe and fixed it myself. I replaced the pump (and filter, but I don't think this was essential) myself for about $100 for new parts from teamcherokee.com/Emissions. Taking my time, it took me about 40 minutes to replace the pump and filter.
After less then 10 min of driving the CEL went off. And it's stayed off. Finally.
There are 3 bolts holding on the LDP and filter. I took these off and pulled off the hoses, which were in good shape. Removing these three bolts and tugging off the hoses allowed the whole assembly to be removed, and replacement was easy. I also removed the negative battery cable prior to doing this. The little red tab on the LDP needs to be popped up before the power connect can be removed. Be careful not to break it.
This thread was a lifesaver. We have been chasing this CEL ghost with a p0455 code. We have spent hundreds of dollars replacing parts "it could be". We finally got to the point where we were living with it since it was an intermittent CEL that would stay on for 500 miles or so. But after I switched out my exhaust the CEL came on and stayed on. Out of frustration I finally found this thread and the CEL has finally gone off. Hopefully it's gone for good. Just for anyone interested I installed a dynomax exhaust for my 2001 Cherokee and went from 17mpg to 21mpg!
An easy fix but time consuming and it will cost you about 90 bones. Basically, the gasket around the fuel regulator has gone bad and causing the fumes to exhaust into your cabin thru the electrical portals. The only way to get at the FR is to drop the tank. It only takes about 30 minutes to do this. Before I get into the details, I would make sure you have access to the part. I had to special order the FR as Chrysler wants to sell the entire fuel pump assemble for about $300. I thought about making my own gasket but as you will see, because the regulator can now move about on top of the fuel pump, it actually does damage the fitting and only get worse over time. Another sympton you might be experiencing is the engine does not start straight away, the reason, the FR is not keeping fuel pressure and the pump has to reinitiate fuel to the fuel rail. If sitting, the pressue leaks down thus, the large or gross leak code you are getting.
Back to dropping the tank, DISCONNECT THE BATTERY before you do anything.
1. remove the tank straps. There is a 14mm nut which needs to be loosened in order to remove the strap hangers. No need to remove the nut entirely, just enough to "unhang" the strap from the bottom of the floor. I proped the tank with small "hard" cooler to keep the tank in place as I was removing the straps. Let the straps drop as the front the strap will allow the tank to drop.
2. Remove the fuel, short connector which connects the fuel line to the actual tank. You will have to press in the pins on each side to remove this short line both at the line and the tank. Not a big deal, use your fingers.
3. remove the vacuum line to the center of the tank.
4. Unplug the electical to the tank. This is a pain the *** so be careful not to damage the plug. I damaged my plug to a degree, in that I broke off the outer piece as it was sealed from years of grime, mud, etc. I used a tie to put back together thru the wires and around the plug to make sure the plug would stay connected. I then lubricated well to help with sealing and then tapped with electrical to form a barrier to keep out the grime to assit the next victim.
5. remove the plate underneath the fuel door to access the vent hose and the fule hose. remove the two clamps. I actually replaced the vent hose as mine was starting to rot. After pulling the hoses off, put an old clean rag into the hoses and tape. As you are moving the hoses thru the frame, this will prevent dirt from getting in the hose.
6. slowly, push the tank away from the fuel door and pull the hoses thru the frame to allow the tank to be completely removed.
7. Remove the FR, make sure to clean the grime around the portal and make ready for the replacement.
8. Replace part and reverse step the process.
I would suggest that while a new regulator may have fixed your issue with fuel smells, a more in depth diagnostic is required before buying and installing any parts. Searching for actually liquid fuel would be the first step. Leaky fuel lines, a misplaced fuel pump assembly gasket, failed fuel injectors, or leaky fuel injector o-rings, or a leaky fuel rail would be a more likely reason foe fuel vapors. Next, inspect for problems with the EVAP system and EVAP hoses.
P0455 JEEP - EVAP System Large Leak
- Check Engine Light ON
- Possible a noticeable fuel odor caused by the release of fuel vapors
- Missing or loose fuel cap
- Incorrect fuel filler cap used
- Loose or damaged gas tank fill hose or vent hose
- Fuel filler cap remains open or fails to close
- Foreign matter caught in fuel filler cap
- Faulty fuel pump assembly gasket
- EVAP canister or fuel tank leaks
- EVAP system hose leaking
- Fuel tank leaking
P0455 JEEP Description - The Evaporative emissions (EVAP) system is design to prevent the escape of fuel vapors from the fuel system. Leaks in the system, ca 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 LDP 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.
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I have a 2000 wrangler 2.5. I have a P0455 evap code. In tracing the lines from the gas tank I noticed that most of the line is metal and seems to be rusting and has pin holes. Can this be replaced with a rubber line?