Tater114

I'm just a back yard mechanic that doesn't know s***, but have been able to figure out a whole lot of s*** over the years. 2004 Jeep Cherokee with 4.0L w/auto. Check engine light came on, did code reader, P0442. Know its vacuum leak so did smoke test and it leaks at the throttle body bell crank. Repair manual does not say if seal or bushing can be replaced? And there's no listing at any of the auto parts stores to replace the throttle body. How would you go about fixing?? Any help I greatly thank you for.

bluejeep2001

Thats a minor leak, and common...your issue is some of the big lines that run down along drivers firewall and back...also check the smaller plastic lines that run from intake along firewall to smog stuff by pass firewall

Tater114

Thank you for getting back to me. I had done a smoke test and even plugged of the breather in the back of the car, so I know all the hoses and connections are good. It is leaking where the bell crank shaft goes into the throttle body. None of the parts stores seem to carry the throttle body anymore. I've found a used one on Ebay but I'm afraid it might have the same problem. Has anyone replaced the bushing or seal for the bell crank shaft in the throttle body? If so could you give me a hint of what I might need to do before I teardown my daily driver. Thank you for any help.

bluejeep2001

What is your idle rpm at idle...to have a leaking shaft on the t/b trigger a fault is almost impossible...every time you step on the gas pedal. you open and enormous vacuum leak when the butterfly opens and if your idle is not high then the iac can counteract it and the system would not know the difference between a leaking shaft body and the iac opening to maintain idle

Tater114

Thank you for your reply. Your information that the throttle body couldn't trip the code, caught me off guard...so I went back and ran smoke test again and at first same results. Come to find out the test port that you normally hook the smoke machine to, "Schrader valve" is leaking. And the way that I found that is I hooked smoke machine straight to hose before the test port and yes it leaked. The Schrader valve will not tighten up, stripped, so going to just do away with test port and hook the hose straight up. I've cleared the code and now we wait...lol. Thank you for the Information and help. You saved me money because if the throttle body had been available at the parts store I would have already bought one. Thanks again!

94zj318

P0442, P0455, and P0456 are small, medium, and large EVAP leak codes. They'll typically all show up together, but sometimes they'll each show up on their own. Pretty much every WJ (at least with the 4.0) will have that code (mine included). Things to check would be the gas cap (to see if it's sealing correctly, and if not, get a new gas cap), as well as hoses in the engine conpartment to see if any are cracked or not making a tight connection. You might want to find a shop that has a smoke machine to test for leaks if it's in the exhaust system. The 4.0, unlike the 4.7 V8, doesn't have an EGR valve, and that's a big problem with those (we had an '05 WK Grand Cherokee, and the mechanic who worked on it said how difficult it was just to get to it to replace it). Once you check everything, clear out the codes. If you're in a state that allows for historic registration on vehicles 20+ years or older (it's hard to believe all of our WJ's are finally THAT old LOL), then you likely don't need to worry about state or emissions inspections (at least we don't here in MD). I hope this gives you a bit of insight. 😊

-Vince

Tater114

Thank you for the information. I believe doing away with leaking "Shrader Valve" fixed problem, at least check engine light hasn't come back on. I do own a smoke machine and use it because I try to do all my own repairs to my vehicles and have needed a smoke machine on several recent repairs. My state is divided on emissions testing it depends on which county you live in and thankfully my county isn't doing emissions testing at this time but has said that they will sometime in future. But we still have to pass state inspections and I have witnessed that I pass state inspection a whole lot easier if the check engine light is not on and this is why I'm fixing this problem. Thank you again kind folks! You have been truly helpful.